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exar corporation 48720 kato road, fremont ca, 94538 ? (510) 668-7000 ? fax (510) 668-7017 ? www.exar.com XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator october 2003 rev. 1.0.2 general description the XRT75L06 is a six channel fully integrated line interface unit (liu) for e3/ds3/sts-1 applications. the liu incorporates 6 independent receivers, transmitters and jitter attenuators in a single 217 lead bga package. each channel of the XRT75L06 can be independently configured to operate in e3 (34.368 mhz), ds3 (44.736 mhz) or sts-1 (51.84 mhz). each transmitter can be turned off and tri-stated for redundancy support or for conserving power. the XRT75L06s differential receiver provides high noise interference margin and is able to receive data over 1000 feet of cable or with up to 12 db of cable attenuation. the XRT75L06 incorporates an advanced crystal- less jitter attenuator per channel that can be selected either in the transmit or receive path. the jitter attenuator performance meets the etsi tbr-24 and bellcore gr-499 specifications. the XRT75L06 provides a parallel microprocessor interface for programming and control. the XRT75L06 supports analog, remote and digital loop-backs. the device also has a built-in pseudo random binary sequence (prbs) generator and detector with the ability to insert and detect single bit error for diagnostic purposes. applications e3/ds3 access equipment dslams digital cross connect systems csu/dsu equipment routers fiber optic terminals f igure 1. b lock d iagram of the xrt 75l06 ordering information p art n umber p ackage o perating t emperature r ange XRT75L06ib 217 lead bga -40 c to +85 c XRT75L06 XRT75L06 channel 5 channel 0 channel n... device monitor mtip_n mring_n dmo_n timing control tx pulse shaping hdb3/ b3zs encoder tx control jitter attenuator mux line driver remote loopback hdb3/ b3zs decoder mux agc/ equalizer peak detector los detector slicer jitter attenuator m processor interface local loopback clock & data recovery clock synthesizer rd wr addr[7:0] cs int d[7:0] txon txclk_n txpos_n txneg_n rxclk_n rxpos_n rxneg/lcv_n rlos_n rlol_n rtip_n rring_n ttip_n tring_n clkout_n sfm_en e3clk ds3clk sts-clk/12m ict pmode rdy pclk reset
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 2 features receiver on chip clock and data recovery circuit for high input jitter tolerance meets e3/ds3/sts-1 jitter tolerance requirement detects and clears los as per g.775 receiver monitor mode handles up to 20 db flat loss with 6 db cable attenuation on chip b3zs/hdb3 encoder and decoder that can be either enabled or disabled on-chip clock synthesizer provides the appropriate rate clock from a single 12.288 mhz clock provides low jitter output clock transmitter compliant with bellcore gr-499, gr-253 and ansi t1.102 specification for transmit pulse tri-state transmit output capability for redundancy applications each transmitter can be turned on or off jitter attenuator on chip advanced crystal-less jitter attenuator for each channel jitter attenuator can be selected in receive, transmit path, or disabled meets etsi tbr 24 jitter transfer requirements compliant with jitter transfer template outlined in itu g.751, g.752, g.755 and gr-499-core,1995 standards 16 or 32 bits selectable fifo size control and diagnostics parallel microprocessor interface for control and configuration supports optional internal transmit driver monitoring each channel supports analog, remote and digital loop-backs single 3.3 v 5% power supply 5 v tolerant digital inputs available in 217 pin bga package - 40c to 85c industrial temperature range transmit interface characteristics accepts either single-rail or dual-rail data from terminal equipment and generates a bipolar signal to the line integrated pulse shaping circuit built-in b3zs/hdb3 encoder (which can be disabled) accepts transmit clock with duty cycle of 30%- 70% generates pulses that comply with the itu-t g.703 pulse template for e3 applications generates pulses that comply with the dsx-3 pulse template, as specified in bellcore gr-499 -core and ansi t1.102_1993 generates pulses that comply with the stsx-1 pulse template, as specified in bellcore gr-253- core transmitter can be turned off in order to support redundancy designs receive interface characteristics integrated adaptive receive equalization (optional) for optimal clock and data recovery declares and clears the los defect per itu-t g.775 requirements for e3 and ds3 applications meets jitter tolerance requirements, as specified in itu-t g.823_1993 for e3 applications meets jitter tolerance requirements, as specified in bellcore gr-499-core for ds3 applications declares loss of lock (lol) alarm built-in b3zs/hdb3 decoder (which can be disabled) recovered data can be muted while the los condition is declared outputs either single-rail or dual-rail data to the terminal equipment
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 3 f igure 2. XRT75L06 in bga package (b ottom v iew ) 1 17 16 15 14 12 12 3 2 7 6 5 4 11 10 9 8 u t r p n m l k j h g f e d c b a (see pin list for pin names and function) XRT75L06
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 i table of contents general description ................................................................................................. 1 a pplications .............................................................................................................................. ................ 1 figure 1. block diagram of the xrt 75l06 ...................................................................................... ................ 1 ordering information .......................................................................................................... ......... 1 f eatures .............................................................................................................................. ...................... 2 t ransmit i nterface c haracteristics ...................................................................................................... 2 r eceive i nterface c haracteristics ........................................................................................................ 2 figure 2. XRT75L06 in bga package (bottom view) ............................................................................... ........ 3 pin descriptions (by function) .............................................................................. 4 t ransmit i nterface .............................................................................................................................. ..... 4 r eceive i nterface .............................................................................................................................. ....... 6 c lock i nterface .............................................................................................................................. .......... 8 control and alarm interface ................................................................................................... .... 9 a nalog p ower and g round ................................................................................................................... 12 digital p ower and g round ..................................................................................................................... 14 1.0 clock synthesizer ......................................................................................................... .................... 16 1.1 c lock d istribution .............................................................................................................................. ......... 16 figure 4. clock distribution congifured in e3 mode without using sfm ....................................................... 16 figure 3. simplified block diagram of the input clock circuitry driving the microprocessor .......................... 16 2.0 the receiver section ...................................................................................................... ................. 17 figure 5. receive path block diagram .......................................................................................... ................. 17 2.1 r eceive l ine i nterface .............................................................................................................................. ... 17 figure 6. receive line interfaceconnection .................................................................................... ............... 17 2.2 a daptive g ain c ontrol (agc) ..................................................................................................................... 18 2.3 r eceive e qualizer .............................................................................................................................. .......... 18 figure 7. acg/equalizer blcok diagram ......................................................................................... ................ 18 2.3.1 recommendations for equalizer settings .................................................................................. ..... 18 2.4 c lock and d ata r ecovery .......................................................................................................................... 18 2.4.1 data/clock recovery mode ................................................................................................ ............... 18 2.4.2 training mode ........................................................................................................... .......................... 18 2.5 los (l oss of s ignal ) d etector .................................................................................................................. 19 2.5.1 ds3/sts-1 los condition ................................................................................................. ................ 19 2.5.2 disabling alos/dlos detection ........................................................................................... ........... 19 t able 1: t he alos (a nalog los) d eclaration and c learance t hresholds for a given setting of losthr and reqen (ds3 and sts-1 a pplications ) ................................................................... 19 2.5.3 e3 los condition: ....................................................................................................... ...................... 20 figure 8. loss of signal definition for e3 as per itu-t g.775 ................................................................. ...... 20 figure 9. loss of signal definition for e3 as per itu-t g.775. ................................................................ ....... 20 2.5.4 interference tolerance .................................................................................................. ..................... 21 figure 10. interference margin test set up for ds3/sts-1 ...................................................................... ...... 21 figure 11. interference margin test set up for e3. ............................................................................ ............. 21 t able 2: i nterference m argin t est r esults .............................................................................................. 22 2.5.5 muting the recovered data with los condition: ........................................................................... . 23 2.6 b3zs/hdb3 d ecoder .............................................................................................................................. ...... 23 figure 12. receiver data output and code violation timing ..................................................................... ....... 23 3.0 the transmitter section ................................................................................................... ............... 24 figure 13. transmit path block diagram ........................................................................................ ................ 24 3.1 t ransmit d igital i nput i nterface ................................................................................................................ 24 figure 14. typical interface between terminal equipment and the XRT75L06 (dual-rail data) ....................... 24 figure 15. transmitter terminal input timing .................................................................................. ............... 25 figure 16. single-rail or nrz data format (encoder and decoder are enabled) ......................................... 25 3.2 t ransmit c lock .............................................................................................................................. .............. 26 3.3 b3zs/hdb3 e ncoder .............................................................................................................................. ...... 26
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 ii 3.3.1 b3zs encoding ........................................................................................................... ....................... 26 3.3.2 hdb3 encoding ........................................................................................................... ....................... 26 figure 17. dual-rail data format (encoder and decoder are disabled) ......................................................... 2 6 figure 18. b3zs encoding format ............................................................................................... .................. 26 3.4 t ransmit p ulse s haper .............................................................................................................................. . 27 figure 20. transmit pulse shape test circuit .................................................................................. .............. 27 3.4.1 guidelines for using transmit build out circuit ......................................................................... .... 27 figure 19. hdb3 encoding format ............................................................................................... ................. 27 3.5 e3 line side parameters .............................................................................................................................. 28 figure 21. pulse mask for e3 (34.368 mbits/s) interface as per itu-t g.703 ................................................... 28 t able 3: e3 t ransmitter line side output and receiver line side input specifications .......................... 29 figure 22. bellcore gr-253 core transmit output pulse template for sonet sts-1 applications ......... 30 t able 4: sts-1 p ulse m ask e quations ........................................................................................................ 30 t able 5: sts-1 t ransmitter l ine s ide o utput and r eceiver l ine s ide i nput s pecifications (gr-253) . 31 figure 23. transmit ouput pulse template for ds3 as per bellcore gr-499 ................................................ 31 t able 7: ds3 t ransmitter l ine s ide o utput and r eceiver l ine s ide i nput s pecifications (gr-499) .... 32 t able 6: ds3 p ulse m ask e quations ........................................................................................................... 32 3.6 t ransmit d rive m onitor .............................................................................................................................. 33 3.7 t ransmitter s ection o n /o ff ....................................................................................................................... 33 figure 24. transmit driver monitor set-up. .................................................................................... ................. 33 4.0 jitter .................................................................................................................... .............................. 34 4.1 j itter t olerance .............................................................................................................................. ............ 34 4.1.1 ds3/sts-1 jitter tolerance requirements ................................................................................. ..... 34 figure 25. jitter tolerance measurements ...................................................................................... ............... 34 4.1.2 e3 jitter tolerance requirements ........................................................................................ ............ 35 figure 26. input jitter tolerance for ds3/sts-1 .............................................................................. ............ 35 figure 27. input jitter tolerance for e3 ..................................................................................... .................... 35 4.2 j itter t ransfer .............................................................................................................................. .............. 36 4.3 j itter a ttenuator .............................................................................................................................. .......... 36 t able 8: j itter a mplitude versus m odulation f requency (j itter t olerance ) ....................................... 36 t able 9: j itter t ransfer s pecification /r eferences ................................................................................. 36 4.3.1 jitter generation ....................................................................................................... ......................... 37 t able 10: j itter t ransfer p ass m asks ....................................................................................................... 37 figure 28. jitter transfer requirements and jitter attenuator performance .................................................. 37 5.0 diagnostic features ....................................................................................................... .................. 38 5.1 prbs g enerator and d etector ................................................................................................................. 38 figure 29. prbs mode .......................................................................................................... ....................... 38 5.2 loopbacks ................................................................................................................. ............................... 39 5.2.1 analog loopback ......................................................................................................... ............... 39 figure 30. analog loopback .................................................................................................... ....................... 39 5.2.2 digital loopback ........................................................................................................ ................. 40 5.2.3 remote loopback ......................................................................................................... ............... 40 figure 31. digital loopback ................................................................................................... ......................... 40 figure 32. remote loopback .................................................................................................... ..................... 40 5.3 transmit all ones (taos) .................................................................................................. .................. 41 figure 33. transmit all ones (taos) ........................................................................................... .................. 41 6.0 microprocessor interface block ............................................................................................ ......... 42 t able 11: s electing the m icroprocessor i nterface m ode ...................................................................... 42 figure 34. simplified block diagram of the microprocessor interface block .................................................. 42 6.1 t he m icroprocessor i nterface b lock s ignals ........................................................................................ 43 t able 12: XRT75L06 m icroprocessor i nterface s ignals ......................................................................... 43 6.2 a synchronous and s ynchronous d escription ......................................................................................... 44 t able 13: a synchronous t iming s pecifications ......................................................................................... 45 figure 35. asynchronous p interface signals during programmed i/o read and write operations ........... 45 figure 36. synchronous p interface signals during programmed i/o read and write operations ............ 46 t able 14: s ynchronous t iming s pecifications ........................................................................................... 46
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 iii figure 37. interrupt process .................................................................................................. .......................... 47 6.2.1 hardware reset: ......................................................................................................... ........................ 48 t able 15: r egister m ap and b it n ames ........................................................................................................ 48 t able 16: r egister m ap d escription - g lobal ............................................................................................ 49 t able 17: r egister m ap and b it n ames - c hannel n r egisters ( n = 0,1,2,3,4,5) ...................................... 49 t able 18: r egister m ap d escription - c hannel n ....................................................................................... 51 7.0 electrical characteristics ................................................................................................ . 56 t able 19: a bsolute m aximum r atings .......................................................................................................... 56 t able 20: dc e lectrical c haracteristics : ................................................................................................. 56 appendix a .................................................................................................................... 57 t able 21: transformer recommendations ..................................................................................... 57 t able 22: t ransformer d etails ................................................................................................................... 57 ordering information .......................................................................................................... ....... 59 .............................................................................................................................. .................................... 59 p ackage d imensions - 23 x 23 mm 217 l ead bga package .................................................................. 59
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 4 pin descriptions ( by function ) transmit interface l ead #s ignal n ame t ype d escription t15 r16 r15 n14 p14 p13 txon_0 txon_1 txon_2 txon_3 txon_4 txon_5 i transmitter on input - channel 0: transmitter on input - channel 1: transmitter on input - channel 2: transmitter on input - channel 3: transmitter on input - channel 4: transmitter on input - channel 5: these pins are active only when the corresponding txon bits are set. table below shows the status of the transmitter based on thetxon bit and txon pin settings. n otes : 1. these pins will be active and can control the ttip and tring outputs only when the txon_n bits in the channel register are set . 2. when transmitters are turned off the ttip and tring outputs are tri- stated. 3. these pins are internally pulled up. e3 m3 f15 p16 g3 h15 txclk_0 txclk_1 txclk_2 txclk_3 txclk_4 txclk_5 i transmit clock input for tpos and tneg - channel 0: transmit clock input for tpos and tneg - channel 1: transmit clock input for tpos and tneg - channel 2: transmit clock input for tpos and tneg - channel 3: transmit clock input for tpos and tneg - channel 4: transmit clock input for tpos and tneg - channel 5: the frequency accuracy of this input clock must be of nominal bit rate 20 ppm. the duty cycle can be 30%-70%. by default, input data is sampled on the falling edge of txclk. bit 0 0 transmitter status off off pin 0 1 1 1 off on 0 1
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 5 f2 p2 g15 r17 h3 k15 tneg_0 tneg_1 tneg_2 tneg_3 tneg_4 tneg_5 i transmit negative data input - channel 0: transmit negative data input - channel 1: transmit negative data input - channel 2: transmit negative data input - channel 3: transmit negative data input - channel 4: transmit negative data input - channel 5: in dual-rail mode, these pins are sampled on the falling or rising edge of txclk_n . n otes : 1. these input pins are ignored and must be grounded if the transmitter sec- tion is configured to accept single-rail data from the terminal equipment. f3 n3 f16 p15 g2 j15 tpos_0 tpos_1 tpos_2 tpos_3 tpos_4 tpos_5 i transmit positive data input - channel 0: transmit positive data input - channel 1: transmit positive data input - channel 2: transmit positive data input - channel 3: transmit positive data input - channel 4: transmit positive data input - channel 5: by default sampled on the falling edge of txclk. d1 n1 d17 n17 h1 h17 ttip_0 ttip_1 ttip_2 ttip_3 ttip_4 ttip_5 o transmit ttip output - channel 0: transmit ttip output - channel 1: transmit ttip output - channel 2: transmit ttip output - channel 3: transmit ttip output - channel 4: transmit ttip output - channel 5: these pins along with tring transmit bipolar signals to the line using a 1:1 trans- former. e1 m1 e17 m17 j1 j17 tring_0 tring_1 tring_2 tring_3 tring_4 tring_5 o transmit ring output - channel 0: transmit ring output - channel 1: transmit ring output - channel 2: transmit ring output - channel 3: transmit ring output - channel 4: transmit ring output - channel 5: these pins along with ttip transmit bipolar signals to the line using a 1:1 trans- former. transmit interface l ead #s ignal n ame t ype d escription
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 6 receive interface l ead #s ignal n ame t ype d escription a2 u2 a17 u17 d8 p8 rxclk_0 rxclk_1 rxclk_2 rxclk_3 rxclk_4 rxclk_5 o receive clock output - channel 0: receive clock output - channel 1: receive clock output - channel 2: receive clock output - channel 3: receive clock output - channel 4: receive clock output - channel 5: by default, rpos and rneg data sampled on the rising edge rxclk.. set the rxclkinv bit to sample rpos/rneg data on the falling edge of rxclk a1 u1 a16 u16 d9 p9 rpos_0 rpos_1 rpos_2 rpos_3 rpos_4 rpos_5 o receive positive data output - channel 0: receive positive data output - channel 1: receive positive data output - channel 2: receive positive data output - channel 3: receive positive data output - channel 4: receive positive data output - channel 5: n ote : if the b3zs/hdb3 decoder is enabled in single-rail mode, then the zero suppression patterns in the incoming line signal (such as: "00v", "000v", "b0v", "b00v") are removed and replaced with 0. b2 t2 b16 t16 d10 p10 rneg_0/ lcv_0 rneg_1/ lcv_1 rneg_2/ lcv_2 rneg_3/ lcv_3 rneg_4/ lcv_4 rneg_5/ lcv_5 o receive negative data output/line code violation indicator - channel 0: receive negative data output/line code violation indicator - channel 1: receive negative data output/line code violation indicator - channel 2: receive negative data output/line code violation indicator - channel 3: receive negative data output/line code violation indicator - channel 4: receive negative data output/line code violation indicator - channel 5: in dual rail mode, a negative pulse is output through rneg. line code violation indicator - channel n: if configured in single rail mode then line code violation will be output. a5 u5 a14 u14 a9 u9 rring_0 rring_1 rring_2 rring_3 rring_4 rring_5 i receive input - channel 0: receive input - channel 1: receive input - channel 2: receive input - channel 3: receive input - channel 4: receive input - channel 5: these pins along with rtip receive the bipolar line signal from the remote ds3/ e3/sts-1 terminal.
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 7 a6 u6 a13 u13 a10 u10 rtip_0 rtip_1 rtip_2 rtip_3 rtip_4 rtip_5 i receive input - channel 0: receive input - channel 1: receive input - channel 2: receive input - channel 3: receive input - channel 4: receive input - channel 5: these pins along with rring receive the bipolar line signal from the remote ds3/e3/sts-1 terminal. receive interface l ead #s ignal n ame t ype d escription
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 8 clock interface l ead #s ignal n ame t ype d escription e15 e3clk i e3 clock input (34.368 mhz 20 ppm): if any of the channels is configured in e3 mode, a reference clock 34.368 mhz is applied on this pin. n ote : in single frequency mode, this reference clock is not required. g16 ds3clk i ds3 clock input (44.736 mhz 20 ppm): if any of the channels is configured in ds3 mode, a reference clock 44.736 mhz. is applied on this pin. n ote : in single frequency mode, this reference clock is not required. c16 sts-1clk/ 12m i sts-1 clock input (51.84 mhz 20 ppm): if any of the channels is configured in sts-1 mode, a reference clock 51.84 mhz is applied on this pin.. in single frequency mode, a reference clock of 12.288 mhz 20 ppm is con- nected to this pin and the internal clock synthesizer generates the appropriate clock frequencies based on the configuration of the channels in e3, ds3 or sts-1 modes. l15 sfm_en i single frequency mode enable: tie this pin high to enable the single frequency mode. a reference clock of 12.288 mhz 20 ppm is applied. in the single frequency mode (sfm) a low jitter output clock is provided for each channel if the clk_en bit is set thus eliminating the need for a separate clock source for the framer. tie this pin low if single frequency mode is not selected. in this case, the appropriate reference clocks must be provided. n ote : this pin is internally pulled down b1 t1 b17 t17 d11 p11 clkout_0 clkout_1 clkout_2 clkout_3 clkout_4 clkout_5 o clock output for channel 0 clock output for channel 1 clock output for channel 2 clock output for channel 3 clock output for channel 4 clock output for channel 5 low jitter clock output for each channel based on the mode selection (e3,ds3 or sts-1) if the clkouten_n bit is set in the control register. this eliminates the need for a separate clock source for the framer. n otes : 1. the maximum drive capability for the clockouts is 16 ma. 2. this clock out is available both in sfm and non-sfm modes.
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 9 control and alarm interface l ead #s ignal n ame t ype d escription b7 r6 c14 r14 c6 d14 mring_0 mring_1 mring_2 mring_3 mring_4 mring_5 i monitor ring input - channel 0: monitor ring input - channel 1: monitor ring input - channel 2: monitor ring input - channel 3: monitor ring input - channel 4: monitor ring input - channel 5: the bipolar line output signal from tring_n is connected to this pin via a 270 w resistor to check for line driver failure. n ote : this pin is internally pulled up. b8 r7 c13 r13 c7 d13 mtip_0 mtip_1 mtip_2 mtip_3 mtip_4 mtip_5 i monitor tip input - channel 0: monitor tip input - channel 1: monitor tip input - channel 2: monitor tip input - channel 3: monitor tip input - channel 4: monitor tip input - channel 5: the bipolar line output signal from ttip_n is connected to this pin via a 270- ohm resistor to check for line driver failure. n ote : this pin is internally pulled up. c5 t4 b12 t12 d5 b15 dmo_0 dmo_1 dmo_2 dmo_3 dmo_4 dmo_5 o drive monitor output - channel 0: drive monitor output - channel 1: drive monitor output - channel 2: drive monitor output - channel 3: drive monitor output - channel 4: drive monitor output - channel 5: if mtip_n and mring_n has no transition pulse for 128 32 txclk_n cycles, dmo_n goes high to indicate the driver failure. dmo_n output stays high until the next ami signal is detected. c8 t7 c12 t11 b11 r8 rlos_0 rlos_1 rlos_2 rlos_3 rlos_4 rlos_5 o receive loss of signal - channel 0: receive loss of signal - channel 1: receive loss of signal - channel 2: receive loss of signal - channel 3: receive loss of signal - channel 4: receive loss of signal - channel 5: this output pin toggles "high" if the receiver has detected a loss of signal con- dition.
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 10 c9 t8 d12 r11 c11 r9 rlol_0 rlol_1 rlol_2 rlol_3 rlol_4 rlol_5 o receive loss of lock - channel 0: receive loss of lock - channel 1: receive loss of lock - channel 2: receive loss of lock - channel 3: receive loss of lock - channel 4: receive loss of lock - channel 5: this output pin toggles "high" if a loss of lock condition is detected. lol (loss of lock) condition occurs if the recovered clock frequency deviates from the reference clock frequency (available at either e3clk or ds3clk or sts- 1clk input pins) by more than 0.5%. l16 rxa **** external resistor of 3.01k w 1%. should be connected between rxa and rxb for internal bias. k16 rxb **** external resistor of 3.01k w 1%. should be connected between rxa and rxb for internal bias. p12 ict i in-circuit test input: setting this pin "low" causes all digital and analog outputs to go into a high- impedance state to allow for in-circuit testing. for normal operation, tie this pin "high". n ote : this pin is internally pulled up. r12 test **** factory test pin n ote : this pin must be connected to gnd for normal operation. control and alarm interface microprocessor interface l ead # s ignal n ame t ype d escription k3 cs i chip select tie this low to enable the communication with the microprocessor interface. r1 pclk i processor clock input to operate the microprocessor interface, appropriate clock frequency is pro- vided through this pin. maximum frequency is 66 mhz. k2 wr i write data : to write data into the registers, this active low signal is asserted. l2 rd i read data: to read data from the registers, this active low pin is asserted. j3 reset i register reset: setting this input pin "low" resets the contents of the command registers to their default settings and default operating configuration n ote : this pin is internally pulled up. l3 pmode i processor mode select: when this pin is tied high, the microprocessor is operating in synchronous mode which means that clock must be applied to the pclk (pin 55). tie this pin low to select the asynchronous mode. an internal clock is pro- vided for the microprocessor interface.
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 11 t3 rdy o ready acknowledge: n ote : this pin must be connected to vdd via 3 k w 1% resistor. u3 int o interrupt output: a transition to low indicates that an interrupt has been generated. the inter- rupt function can be disabled by clearing the interrupt enable bit in the channel control register . n otes : 1. this pin will remain asserted low until the interrupt is serviced. 2. this pin must be conneced to vdd via 3 k w 1% resistor. b4 a3 b3 c4 c3 c2 d3 d4 addr[0] addr[1] addr[2] addr[3] addr[4] addr[5] addr[6] addr[7] i address bus: 8 bit address bus for the microprocessor interface n4 p3 p4 p5 r5 r4 r3 r2 d[0] d[1] d[2] d[3] d[4] d[5] d[6] d[7] i/o data bus: 8 bit data bus for the microprocessor interface microprocessor interface l ead #s ignal n ame t ype d escription
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 12 analog power and ground l ead #s ignal n ame t ype d escription e2 txavdd_0 **** transmitter analog 3.3 v 5% vdd - channel 0 n2 txavdd_1 **** transmitter analog 3.3 v 5% vdd - channel 1 e16 txavdd_2 **** transmitter analog 3.3 v 5% vdd - channel 2 n16 txavdd_3 **** transmitter analog 3.3 v 5% vdd - channel 3 j2 txavdd_4 **** transmitter analog 3.3 v 5% vdd - channel 4 j16 txavdd_5 **** transmitter analog 3.3 v 5% vdd - channel 5 d2 txagnd_0 **** transmitter analog gnd - channel 0 m2 txagnd_1 **** transmitter analog gnd - channel 1 d16 txagnd_2 **** transmitter analog gnd - channel 2 m16 txagnd_3 **** transmitter analog gnd - channel 3 h2 txagnd_4 **** transmitter analog gnd - channel 4 h16 txagnd_5 **** transmitter analog gnd - channel 5 a4 rxavdd_0 **** receiver analog 3.3 v 5% vdd - channel 0 u4 rxavdd_1 **** receiver analog 3.3 v 5% vdd - channel 1 a15 rxavdd_2 **** receiver analog 3.3 v 5% vdd - channel 2 u15 rxavdd_3 **** receiver analog 3.3 v 5% vdd - channel 3 a8 rxavdd_4 **** receiver analog 3.3 v 5% vdd - channel 4 u8 rxavdd_5 **** receiver analog 3.3 v 5% vdd - channel 5 a7 rxagnd_0 **** receiver analog gnd - channel_0 u7 rxagnd_1 **** receive analog gnd - channel 1 a12 rxagnd_2 **** receive analog gnd - channel 2 u12 rxagnd_3 **** receive analog gnd - channel 3 a11 rxagnd_4 **** receive analog gnd - channel 4 u11 rxagnd_5 **** receive analog gnd - channel 5 e4 jaavdd_0 **** analog 3.3 v 5% vdd - jitter attenuator channel 0 k4 jaavdd_1 **** analog 3.3 v 5% vdd - jitter attenuator channel 1 e14 jaavdd_2 **** analog 3.3 v 5% vdd - jitter attenuator channel 2 k14 jaavdd_3 **** analog 3.3 v 5% vdd - jitter attenuator channel 3 g4 jaavdd_4 **** analog 3.3 v 5% vdd - jitter attenuator channel 4 g14 jaavdd_5 **** analog 3.3 v 5% vdd - jitter attenuator channel 5 f4 jaagnd_0 **** analog gnd - jitter attenuator channel 0 j4 jaagnd_1 **** analog gnd - jitter attenuator channel 1
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 13 f14 jaagnd_2 **** analog gnd - jitter attenuator channel 2 j14 jaagnd_3 **** analog gnd - jitter attenuator channel 3 h4 jaagnd_4 **** analog gnd - jitter attenuator channel 4 h14 jaagnd_5 **** analog gnd - jitter attenuator channel 5 c10 agnd **** analog gnd r10 agnd **** analog gnd h9 agnd **** analog gnd j9 agnd **** analog gnd k9 agnd **** analog gnd n15 refavdd **** analog 3.3 v 5% vdd - reference m15 refgnd **** reference gnd analog power and ground l ead # s ignal n ame t ype d escription
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 14 digital power and ground l ead #s ignal n ame t ype d escription f1 txvdd_0 **** transmitter 3.3 v 5% vdd channel 0 l1 txvdd_1 **** transmitter 3.3 v 5% vdd channel 1 f17 txvdd_2 **** transmitter 3.3 v 5% vdd channel 2 l17 txvdd_3 **** transmitter 3.3 v 5% vdd channel 3 k1 txvdd_4 **** transmitter 3.3 v 5% vdd channel 4 k17 txvdd_5 **** transmitter 3.3 v 5% vdd channel 5 c1 txgnd_0 **** transmitter gnd - channel 0 p1 txgnd_1 **** transmitter gnd - channel 1 c17 txgnd_2 **** transmitter gnd - channel 2 p17 txgnd_3 **** transmitter gnd - channel 3 g1 txgnd_4 **** transmitter gnd - channel 4 g17 txgnd_5 **** transmitter gnd - channel 5 b5 rxdvdd_0 **** receiver 3.3 v 5% vdd - channel 0 t5 rxdvdd_1 **** receiver 3.3 v 5% vdd - channel 1 b14 rxdvdd_2 **** receiver 3.3 v 5% vdd - channel 2 t14 rxdvdd_3 **** receiver 3.3 v 5% vdd - channel 3 b9 rxdvdd_4 **** receiver 3.3 v 5% vdd - channel 4 t9 rxdvdd_5 **** receiver 3.3 v 5% vdd - channel 5 b6 rxdgnd_0 **** receiver digital gnd - channel 0 t6 rxdgnd_1 **** receiver digital gnd - channel 1 b13 rxdgnd_2 **** receiver digital gnd - channel 2 t13 rxdgnd_3 **** receiver digital gnd - channel 3 b10 rxdgnd_4 **** receiver digital gnd - channel 4 t10 rxdgnd_5 **** receiver digital gnd - channel 5 p6 dvdd_1 **** vdd 3.3 v 5% c15 dvdd_2 **** vdd 3.3 v 5% l4 jadvdd_1 **** vdd 3.3 v 5% d6 dvdd(up) **** vdd 3.3 v 5% l14 jadvdd_2 **** vdd 3.3 v 5% d15 dgnd_1 **** digital gnd d7 dgnd(up) **** digital gnd m14 jadgnd_2 **** digital gnd
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 15 m4 jadgnd_1 **** digital gnd p7 dgnd **** digital gnd h8 dgnd **** digital gnd j8 dgnd **** digital gnd k8 dgnd **** digital gnd h10 dgnd **** digital gnd j10 dgnd **** digital gnd k10 dgnd **** digital gnd digital power and ground l ead #s ignal n ame t ype d escription
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 16 1.0 clock synthesizer the liu uses a flexible user interface for accepting clock references to generate the internal master clocks used to drive the liu. the reference clock used to supply the microprocessor timing is generated from the ds- 3 or sfm clock input. therefore, if the chip is configured for sts-1 only or e3 only, then the ds-3 input pin must be connected to the sts-1 pin or e3 pin respectively. in ds-3 mode or when sfm is used, the sts-1 and e3 input pins can be left unconnected. if sfm is enabled by pulling the sfm_en pin "high", 12.288mhz is the only clock reference necessary to generate ds-3, e3, or sts-1 line rates and the microprocessor timing. a simplified block diagram of the clock synthesizer is shown in figure 3 1.1 clock distribution network cards that are designed to support multiple line rates which are not configured for single frequency mode should ensure that a clock is applied to the ds3clk input pin. for example: if the network card being supplied to an isp requires e3 only, the ds-3 input clock reference is still necessary to provide read and write access to the internal microprocessor. therefore, the e3 mode requires two input clock references. if however, multiple line rates will not be supported, i.e. e3 only, then the ds3clk input pin may be hard wire connected to the e3clk input pin. f igure 4. c lock d istribution c ongifured in e3 m ode w ithout u sing sfm n ote : for one input clock reference, the single frequency mode should be used. f igure 3. s implified b lock d iagram of the i nput c lock c ircuitry d riving the m icroprocessor clock synthesizer m processor lol_n ds3clk sfm_en sts-1clk/12m e3clk clkout_n 0 1 clock synthesizer m processor lol_n ds3clk e3clk clkout_n
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 17 2.0 the receiver section the receiver is designed so that the liu can recover clock and data from an attenuated line signal caused by cable loss or flat loss according to industry specifications. once data is recovered, it is processed and presented at the receiver outputs according to the format chosen to interface with a framer/mapper or asic. this section describes the detailed operation of various blocks within the receive path. a simplified block diagram of the receive path is shown in figure 5. f igure 5. r eceive p ath b lock d iagram 2.1 receive line interface physical layer devices are ac coupled to a line interface through a 1:1 transformer. the transformer provides isolation and a level shift by blocking the dc offset of the incoming data stream. the typical medium for the line interface is a 75 w coxial cable. whether using e3, ds-3 or sts-1, the liu requires the same bill of materials, see figure 6. f igure 6. r eceive l ine i nterface c onnection channel n hdb3/ b3zs decoder mux agc/ equalizer peak detector los detector slicer jitter attenuator clock & data recovery rxclk_n rxpos_n rxneg/lcv_n rlos_n rtip_n rring_n ds-3/e3/sts-1 1:1 receiver 75 w rlos_n rtip_n rring_n 37.5 w 0.01 m f 37.5 w
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 18 2.2 adaptive gain control (agc) the adaptive gain control circuit amplifies the incoming analog signal and compensates for the various flat losses and also for the loss at one-half symbol rate. the agc has a dynamic range of 30 db. the peak detector provides feedback to the equalizer before slicing occurs. 2.3 receive equalizer the equalizer restores the integrity of the signal and compensates for the frequency dependent attenuation of up to 900 feet of coaxial cable (1300 feet for e3). the equalizer also boosts the high frequency content of the signal to reduce inter-symbol interference (isi) so that the slicer slices the signal at 50% of peak voltage to generate positive and negative data. the equalizer can be disabled by programming the appropriate register. f igure 7. acg/e qualizer b lcok d iagram 2.3.1 recommendations for equalizer settings the equalizer has two gain settings to provide optimum equalization. in the case of normally shaped ds3/ sts-1 pulses (pulses that meet the template requirements) that has been driven through 0 to 900 feet of cable, the equalizer can be enabled. however, for square-shaped pulses such as e3 or for ds3/sts-1 high pulses (that does not meet the pulse template requirements), it is recommended that the equalizer be disabled for cable length less than 300 feet. this would help to prevent over-equalization of the signal and thus optimize the performance in terms of better jitter transfer characteristics. the equalizer also contains an additional 20 db gain stage to provide the line monitoring capability of the resistively attenuated signals which may have 20db flat loss. the equalizer gain mode can be enabled by programming the appropriate register. n ote : the results of extensive testing indicate that even when the equalizer was enabled, regardless of the cable length, the integrity of the e3 signal was restored properly over 0 to 12 db cable loss at industrial temperature. 2.4 clock and data recovery the clock and data recovery circuit extracts the embedded clock, rxclk_n from the sliced digital data stream and provides the retimed data to the b3zs (hdb3) decoder. the clock recovery pll can be in one of the following two modes: 2.4.1 data/clock recovery mode in the presence of input line signals on the rtip_n and rring_n input pins and when the frequency difference between the recovered clock signal and the reference clock signal is less than 0.5%, the clock that is output on the rxclk_n out pins is the recovered clock signal. 2.4.2 training mode in the absence of input signals at rtip_n and rring_n pins, or when the frequency difference between the recovered line clock signal and the reference clock applied on the exclk_n input pins exceed 0.5%, a loss of lock condition is declared by toggling rlol_n output pin high or setting the rlol_n bit to 1 in the control register. also, the clock output on the rxclk_n pins are the same as the reference channel clock. agc/ equalizer peak detector los detector slicer rtip_n rring_n
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 19 2.5 los (loss of signal) detector 2.5.1 ds3/sts-1 los condition a digital loss of signal (dlos) condition occurs when a string of 175 75 consecutive zeros occur on the line. when the dlos condition occurs, the dlos_n bit is set to 1 in the status control register. dlos condition is cleared when the detected average pulse density is greater than 33% for 175 75 pulses. analog loss of signal (alos) condition occurs when the amplitude of the incoming line signal is below the threshold as shown in the table 1.the status of the alos condition is reflected in the alos_n status control register. rlos is the logical or of the dlos and alos states. when the rlos condition occurs the rlos_n output pin is toggled high and the rlos_n bit is set to 1 in the status control register. 2.5.2 disabling alos/dlos detection for debugging purposes it is useful to disable the alos and/or dlos detection. writing a 1 to both alosdis_n and dlosdis_n bits disables the los detection on a per channel basis. t able 1: t he alos (a nalog los) d eclaration and c learance t hresholds for a given setting of losthr and reqen (ds3 and sts-1 a pplications ) a pplication reqen s etting losthr s etting s ignal l evel to d eclare alos d efect s ignal l evel to c lear alos d efect ds3 0 0 < 75mvpk > 130mvpk 1 0 < 45mvpk > 60mvpk 0 1 < 120mvpk > 45mvpk 1 1 < 55mvpk > 180mvpk sts-1 0 0 < 120mvpk > 170mvpk 1 0 < 50mvpk > 75mvpk 0 1 < 125mvpk > 205mvpk 1 1 < 55mvpk > 90mvpk
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 20 2.5.3 e3 los condition: if the level of incoming line signal drops below the threshold as described in the itu-t g.775 standard, the los condition is detected. loss of signal is defined as no transitions for 10 to 255 consecutive zeros. no transitions is defined as a signal level between 15 and 35 db below the normal. this is illustrated in figure 8. the los condition is cleared within 10 to 255 ui after restoration of the incoming line signal. figure 9 shows the los declaration and clearance conditions. f igure 8. l oss o f s ignal d efinition for e3 as per itu-t g.775 f igure 9. l oss of s ignal d efinition for e3 as per itu-t g.775. 0 db -12 db -15db -35db maximum cable loss for e3 los signal must be declared los signal must be cleared los signal may be cleared or declared actual occurrence of los condition line signal is restored time range for los declaration time range for los clearance g.775 compliance g.775 compliance 0 ui 10 ui 0 ui 10 ui 255 ui 255 ui rtip/ rring rlos output pin
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 21 2.5.4 interference tolerance for e3 mode, itu-t g.703 recommendation specifies that the receiver be able to recover error free clock and data in the presence of a sinusoidal interfering tone signal. for ds3 and sts-1 modes, the same recommendation is being used. figure 10 shows the configuration to test the interference margin for ds3/ sts1. figure 11 shows the set up for e3. f igure 10. i nterference m argin t est s et up for ds3/sts-1 f igure 11. i nterference m argin t est s et up for e3. sine wave generator pattern generator 2 23 -1 prbs n s attenuator ? test equipment dut XRT75L06 ds3 = 22.368 mhz sts-1 = 25.92 mhz cable simulator attenuator 1 n s sine wave generator 17.184mhz signal source 2 23 -1 prbs attenuator 2 ? test equipment dut XRT75L06 cable simulator
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 22 t able 2: i nterference m argin t est r esults m ode c able l ength (a ttenuation )i nterference t olerance e3 0 db equalizer in -17 db 12 db -14 db ds3 0 feet -15 db 225 feet -15 db 450 feet -14 db sts-1 0 feet -15 db 225 feet -14 db 450 feet -14 db
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 23 2.5.5 muting the recovered data with los condition: when the los condition is declared, the clock recovery circuit locks into the reference clock applied to the internal master clock outputs this clock onto the rxclk_n output pin. the data on the rxpos_n and rxneg_n pins can be forced to zero by setting the losmut_n bits in the individual channel control register to 1. n ote : when the los condition is cleared, the recovered data is output on rxpos_n and rxneg_n pins. 2.6 b3zs/hdb3 decoder the decoder block takes the output from the clock and data recovery block and decodes the b3zs (for ds3 or sts-1) or hdb3 (for e3) encoded line signal and detects any coding errors or excessive zeros in the data stream. whenever the input signal violates the b3zs or hdb3 coding sequence for bipolar violation or contains three (for b3zs) or four (for hdb3) or more consecutive zeros, an active high pulse is generated on the rlcv_n output pins to indicate line code violation. f igure 12. r eceiver d ata output and code violation timing symbol parameter min typ max units rxclk duty cycle 45 50 55 % rxclk frequency e3 ds-3 sts-1 34.368 44.736 51.84 mhz mhz mhz t rrx rxclk rise time (10% o 90%) 2 4 ns t frx rxclk falling time (10% to 90%) 2 4 ns t co rxclk to rpos/rneg delay time 4 ns t lcvo rxclk to rising edge of lcv output delay 2.5 ns rxclk t rrx t frx rpos or rneg lcv t lcvo t co
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 24 3.0 the transmitter section the transmitter is designed so that the liu can accept serial data from a local device, encode the data properly, and then output an analog pulse according to the pulse shape chosen in the appropriate registers. this section describes the detailed operation of various blocks within the transmit path. a simplified block diagram of the transmit path is shown in figure 13. f igure 13. t ransmit p ath b lock d iagram 3.1 transmit digital input interface the method for applying data to the transmit inputs of the liu is a serial interface consisting of txclk, txpos, and txneg. for single rail mode, only txclk and txpos are necessary for providing the local data from a framer device or asic. data can be sampled on either edge of the input clock signal by programming the appropriate register. a typical interface is shown in figure 14. f igure 14. t ypical interface between terminal equipment and the XRT75L06 ( dual - rail data ) channel n device monitor mtip_n mring_n dmo_n timing control tx pulse shaping hdb3/ b3zs encoder tx control jitter attenuator mux line driver txon txclk_n txpos_n txneg_n ttip_n tring_n terminal equipment (e3/ds3 or sts-1 framer) exar e3/ds3/sts-1 liu transmit logic block txpos txneg txlineclk tpdata tndata txclk
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 25 f igure 15. t ransmitter t erminal i nput t iming symbol parameter min typ max units txclk duty cycle 30 50 70 % txclk frequency e3 ds-3 sts-1 34.368 44.736 51.84 mhz mhz mhz t rtx txclk rise time (10% to 90%) 4 ns t ftx txclk fall time (10% to 90%) 4 ns t tsu tpdata/tndata to txclk falling set up time 3 ns t tho tpdata/tndata to txclk falling hold time 3 ns f igure 16. s ingle -r ail or nrz d ata f ormat (e ncoder and d ecoder are e nabled ) tpdata or tndata ttip or tring txclk t tsu t tho t rtx t ftx txclk tpdata data 1 1 0
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 26 3.2 transmit clock the transmit clock applied via txclk_n pins, for the selected data rate (for e3 = 34.368 mhz, ds3 = 44.736 mhz or sts-1 = 51.84 mhz), is duty cycle corrected by the internal pll circuit to provide a 50% duty cycle clock to the pulse shaping circuit. this allows a 30% to 70% duty cycle transmit clock to be supplied. 3.3 b3zs/hdb3 e ncoder when the single-rail (nrz) data format is selected, the encoder block encodes the data into either b3zs format (for either ds3 or sts-1) or hdb3 format (for e3). 3.3.1 b3zs encoding an example of b3zs encoding is shown in figure 18. if the encoder detects an occurrence of three consecutive zeros in the data stream, it is replaced with either b0v or 00v, where b refers to bipolar pulse that is compliant with the alternating polarity requirement of the ami (alternate mark inversion) line code and v refers to a bipolar violation (e.g., a bipolar pulse that violates the ami line code). the substitution of b0v or 00v is made so that an odd number of bipolar pulses exist between any two consecutive violation (v) pulses. this avoids the introduction of a dc component into the line signal. 3.3.2 hdb3 encoding an example of the hdb3 encoding is shown in figure 19. if the hdb3 encoder detects an occurrence of four consecutive zeros in the data stream, then the four zeros are substituted with either 000v or b00v pattern. the substitution code is made in such a way that an odd number of pulses exist between any consecutive v pulses. this avoids the introduction of dc component into the analog signal. f igure 17. d ual -r ail d ata f ormat ( encoder and decoder are disabled ) f igure 18. b3zs e ncoding f ormat txclk tpdata tndata data 1 1 0 000 1 1 1 1 1 1 1 v b v 1 0 00 00 0 0 0 0 0 0 0 000 v bv 0 00 tclk line signal tpdata
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 27 3.4 t ransmit p ulse s haper the transmit pulse shaper converts the b3zs encoded digital pulses into a single analog alternate mark inversion (ami) pulse that meets the industry standard mask template requirements for sts-1 and ds3. for e3 mode, the pulse shaper converts the hdb3 encoded pulses into a single full amplitude square shaped pulse with very little slope. the pulse shaper block also includes a transmit build out circuit, which can either be disabled or enabled by setting the txlev_n bit to 1 or 0 in the control register. for ds3/sts-1 rates, the transmit build out circuit is used to shape the transmit waveform that ensures that transmit pulse template requirements are met at the cross-connect system. the distance between the transmitter output and the cross-connect system can be between 0 to 450 feet. for e3 rate, since the output pulse template is measured at the secondary of the transformer and since there is no cross-connect system pulse template requirements, the transmit build out circuit is always disabled. the differential line driver increases the transmit waveform to appropriate level and drives into the 75 w load as shown in figure 20. f igure 20. t ransmit p ulse s hape t est c ircuit 3.4.1 guidelines for using transmit build out circuit if the distance between the transmitter and the dsx3 or stsx-1, cross-connect system, is less than 225 feet, enable the transmit build out circuit by setting the txlev_n control bit to 0. if the distance between the transmitter and the dsx3 or stsx-1 is greater than 225 feet, disable the transmit build out circuit. f igure 19. hdb3 e ncoding f ormat 0 0 000 1 1 1 1 1 1 1 v b v 1 00 00 0 0 0 0 0 0 0 0 00 v 0 00 tclk line signal tpdata ttip(n) tring(n) 1:1 r3 75 w txpos(n) txneg(n) txlineclk(n) tpdata(n) tndata(n) txclk(n) 31.6 w + 1% 31.6 w +1% r1 r2
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 28 3.5 e3 line side parameters the XRT75L06 line output at the transformer output meets the pulse shape specified in itu-t g.703 for 34.368 mbits/s operation. the pulse mask as specified in itu-t g.703 for 34.368 mbits/s is shown in figure 7. f igure 21. p ulse m ask for e3 (34.368 mbits / s ) interface as per itu - t g.703 0% 50% v = 100% 14.55ns nominal pulse 12.1ns (14.55 - 2.45) 17 ns (14.55 + 2.45) 8.65 ns 10% 10% 20%
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 29 n ote : the above values are at ta = 25 0 c and v dd = 3.3 v 5%. t able 3: e3 t ransmitter line side output and receiver line side input specifications parameter min typ max units t ransmitter line side output characteristics transmit output pulse amplitude (measured at secondary of the transformer) 0.90 1.00 1.10 v pk transmit output pulse amplitude ratio 0.95 1.00 1.05 transmit output pulse width 12.5 14.55 16.5 ns transmit intrinsic jitter 0.02 0.05 ui pp r eceiver line side input characteristics receiver sensitivity (length of cable) 900 1200 feet interference margin -20 -14 db jitter tolerance @ jitter frequency 800khz 0.15 0.28 ui pp signal level to declare loss of signal -35 db signal level to clear loss of signal -15 db occurence of los to los declaration time 10 255 ui termination of los to los clearance time 10 255 ui
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 30 f igure 22. b ellcore gr-253 core t ransmit o utput p ulse t emplate for sonet sts-1 a pplications t able 4: sts-1 p ulse m ask e quations t ime in u nit i ntervals n ormalized a mplitude lower curve -0.85 < t < -0.38 - 0.03 -0.38 < t < 0.36 0.36 < t < 1.4 - 0.03 upper curve -0.85 < t < -0.68 0.03 -0.68 < t < 0.26 0.26 < t < 1.4 0.1 + 0.61 x e -2.4[t-0.26] sts-1 pulse template -0.2 0 0.2 0.4 0.6 0.8 1 1.2 -1 -0.9 -0.8 - 0. 7 -0.6 - 0.5 - 0. 4 - 0.3 - 0.2 -0.1 0 0.1 0. 2 0.3 0. 4 0.5 0. 6 0. 7 0.8 0. 9 1 1.1 1. 2 1.3 1. 4 time, in ui normalized amplitude lower curve upper curve 0.5 1 p 2 -- -1 t 0.18 ----------- + ? ? ? ?t y sin + 0.03 C 0.5 1 p 2 -- -1 t 0.34 ----------- + ? ? ? ?t y sin + 0.03 +
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 31 n ote : the above values are at ta = 25 0 c and v dd = 3.3 v 5%. t able 5: sts-1 t ransmitter l ine s ide o utput and r eceiver l ine s ide i nput s pecifications (gr-253) p arameter m in t yp m ax u nits t ransmitter line side output characteristics transmit output pulse amplitude (measured with txlev = 0) 0.65 0.75 0.90 v pk transmit output pulse amplitude (measured with txlev = 1) 0.90 1.00 1.10 v pk transmit output pulse width 8.6 9.65 10.6 ns transmit output pulse amplitude ratio 0.90 1.00 1.10 transmit intrinsic jitter 0.02 0.05 ui pp r eceiver line side input characteristics receiver sensitivity (length of cable) 900 1100 feet jitter tolerance @ jitter frequency 400 khz 0.15 ui pp signal level to declare loss of signal refer to table 10 signal level to clear loss of signal refer to table 10 f igure 23. t ransmit o uput p ulse t emplate for ds3 as per b ellcore gr-499 ds3 pulse template -0.2 0 0.2 0.4 0.6 0.8 1 1.2 -1 - 0.9 - 0 .8 - 0.7 - 0.6 - 0.5 - 0.4 - 0. 3 - 0.2 - 0 .1 0 0. 1 0 . 2 0. 3 0.4 0. 5 0 . 6 0. 7 0 . 8 0. 9 1 1.1 1 . 2 1 . 3 1 . 4 time, in ui normalized amplitude lower curve upper curve
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 32 t able 7: ds3 t ransmitter l ine s ide o utput and r eceiver l ine s ide i nput s pecifications (gr-499) n ote : the above values are at ta = 25 0 c and v dd = 3.3v 5%. t able 6: ds3 p ulse m ask e quations t ime in u nit i ntervals n ormalized a mplitude lower curve -0.85 < t < -0.36 - 0.03 -0.36 < t < 0.36 0.36 < t < 1.4 - 0.03 upper curve -0.85 < t < -0.68 0.03 -0.68 < t < 0.36 0.36 < t < 1.4 0.08 + 0.407 x e -1.84[t-0.36] p arameter m in t yp m ax u nits t ransmitter line side output characteristics transmit output pulse amplitude (measured with txlev = 0) 0.65 0.75 0.85 v pk transmit output pulse amplitude (measured with txlev = 1) 0.90 1.00 1.10 v pk transmit output pulse width 10.10 11.18 12.28 ns transmit output pulse amplitude ratio 0.90 1.00 1.10 transmit intrinsic jitter 0.02 0.05 ui pp r eceiver line side input characteristics receiver sensitivity (length of cable) 900 1100 feet jitter tolerance @ 400 khz (cat ii) 0.15 ui pp signal level to declare loss of signal refer to table 10 signal level to clear loss of signal refer to table 10 0.5 1 p 2 -- -1 t 0.18 ----------- + ? ? ? ?t y sin + 0.03 C 0.5 1 p 2 -- -1 t 0.34 ----------- + ? ? ? ?t y sin + 0.03 +
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 33 3.6 transmit drive monitor this feature is used for monitoring the transmit line for occurrence of fault conditions such as a short circuit on the line or a defective line driver. to activate this function, connect mtip_n pins to the ttip_n lines via a 270 w resistor and mring_n pins to tring_n lines via 270 w resistor as shown in figure 24. when the mtip_n and mring_n are connected to the ttip_n and tring_n lines, the drive monitor circuit monitors the line for transitions. the dmo_n (drive monitor output) will be asserted low as long as the transitions on the line are detected via mtip_n and mring_n. if no transitions on the line are detected for 128 32 txclk_n periods, the dmo_n output toggles high and when the transitions are detected again, dmo_n toggles low. n ote : the drive monitor circuit is only for diagnostic purpose and does not have to be used to operate the transmitter. 3.7 transmitter section on/off the transmitter section of each channel can either be turned on or off. to turn on the transmitter, set the input pin txon to high and write a 1 to the txon_n control bit. when the transmitter is turned off, ttip_n and tring_n are tri-stated. n otes : 1. this feature provides support for redundancy. 2. to permit a system designed for redundancy to quickly shut-off the defective line card and turn on the back-up line card, writing a 1 to the txon_n control bits transfers the control to txon pin. f igure 24. t ransmit d river m onitor set - up . ttip(n) tring(n) 1:1 r3 75 w txpos(n) txneg(n) txlineclk(n) tpdata(n) tndata(n) txclk(n) 31.6 w + 1% 31.6 w +1% r1 r2 mtip(n) mring(n) 270 w 270 w r1 r2
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 34 4.0 jitter there are three fundamental parameters that describe circuit performance relative to jitter jitter tolerance jitter transfer jitter generation 4.1 j itter t olerance jitter tolerance is a measure of how well a clock and data recovery unit can successfully recover data in the presence of various forms of jitter. it is characterized by the amount of jitter required to produce a specified bit error rate. the tolerance depends on the frequency content of the jitter. jitter tolerance is measured as the jitter amplitude over a jitter spectrum for which the clock and data recovery unit achieves a specified bit error rate (ber). to measure the jitter tolerance as shown in figure 25, jitter is introduced by the sinusoidal modulation of the serial data bit sequence. input jitter tolerance requirements are specified in terms of compliance with jitter mask which is represented as a combination of points. each point corresponds to a minimum amplitude of sinusoidal jitter at a given jitter frequency. 4.1.1 ds3/sts-1 jitter tolerance requirements bellcore gr-499 core specifies the minimum requirement of jitter tolerance for category i and category ii. the jitter tolerance requirement for category ii is the most stringent. figure 26 shows the jitter tolerance curve as per gr-499 specification. f igure 25. j itter t olerance m easurements freq synthesizer pattern generator dut XRT75L06 error detector modulation freq. data clock
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 35 4.1.2 e3 jitter tolerance requirements itu-t g.823 standard specifies that the clock and data recovery unit must be able to tolerate jitter up to certain specified limits. figure 27 shows the tolerance curve. as shown in the figures above, in the jitter tolerance measurement, the dark line indicates the minimum level of jitter that the e3/ds3/sts-1 compliant component must tolerate. table 8 below shows the jitter amplitude versus the modulation frequency for various standards. f igure 26. i nput j itter t olerance f or ds3/sts-1 f igure 27. i nput j itter t olerance for e3 0.01 0.03 15 1.5 0.3 2 20 0.15 jitter amplitude (ui pp ) jitter frequency (khz) 10 5 0.3 100 0.1 gr-253 sts-1 gr-499 cat ii gr-499 cat i 64 41 XRT75L06 0.1 1.5 1 10 jitter amplitude (ui pp ) jitter frequency (khz) 800 itu-t g.823 64 10 0.3 XRT75L06
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 36 4.2 j itter t ransfer jitter transfer function is defined as the ratio of jitter on the output relative to the jitter applied on the input versus frequency. there are two distinct characteristics in jitter transfer, jitter gain (jitter peaking) defined as the highest ratio above 0db and jitter transfer bandwidth. the overall jitter transfer bandwidth is controlled by a low bandwidth loop, typically using a voltage-controlled crystal oscillator (vcxo). the jitter transfer function is a ratio between the jitter output and jitter input for a component, or system often expressed in db. a negative db jitter transfer indicates the element removed jitter. a positive db jitter transfer indicates the element added jitter. a zero db jitter transfer indicates the element had no effect on jitter. table 9 shows the jitter transfer characteristics and/or jitter attenuation specifications for various data rates: n ote : the above specifications can be met only with a jitter attenuator that supports e3/ds3/sts-1 rates. 4.3 jitter attenuator an advanced crystal-less jitter attenuator per channel is included in the XRT75L06. the jitter attenuator requires no external crystal nor high-frequency reference clock. by clearing or setting the jatx/rx_n bits in the channel control registers selects the jitter attenuator either in the receive or transmit path on per channel basis. the fifo size can be either 16-bit or 32-bit. the bits ja0_n and ja1_n can be set to appropriate combination to select the different fifo sizes or to disable the jitter attenuator on a per channel basis. data is clocked into the fifo with the associated clock signal (txclk or rxclk) and clocked out of the fifo with the dejittered clock. when the fifo is within two bits of overflowing or underflowing, the fifo limit status bit, fl_n is set to 1 in the alarm status register. reading this bit clears the fifo and resets the bit into default state. n ote : it is recommended to select the 16-bit fifo for delay-sensitive applications as well as for removing smaller amounts of jitter. table 10 specifies the jitter transfer mask requirements for various data rates: t able 8: j itter a mplitude versus m odulation f requency (j itter t olerance ) b it r ate ( kb / s ) s tandard i nput j itter a mplitude (ui p - p ) m odulation f requency a1 a2 a3 f 1(h z ) f 2(h z ) f 3( k h z ) f 4( k h z ) f 5( k h z ) 34368 itu-t g.823 1.5 0.15 - 100 1000 10 800 - 44736 gr-499 core cat i 5 0.1 - 10 2.3k 60 300 - 44736 gr-499 core cat ii 10 0.3 - 10 669 22.3 300 - 51840 gr-253 core cat ii 15 1.5 0.15 10 30 300 2 20 t able 9: j itter t ransfer s pecification /r eferences e3 ds3 sts-1 etsi tbr-24 gr-499 core section 7.3.2 category i and category ii gr-253 core section 5.6.2.1
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 37 the jitter attenuator within the XRT75L06 meets the latest jitter attenuation specifications and/or jitter transfer characteristics as shown in the figure 28. 4.3.1 j itter g eneration jitter generation is defined as the process whereby jitter appears at the output port of the digital equipment in the absence of applied input jitter. jitter generation is measured by sending jitter free data to the clock and data recovery circuit and measuring the amount of jitter on the output clock or the re-timed data. since this is essentially a noise measurement, it requires a definition of bandwidth to be meaningful. the bandwidth is set according to the data rate. in general, the jitter is measured over a band of frequencies. t able 10: j itter t ransfer p ass m asks r ate ( kbits ) m ask f1 (h z ) f2 (h z ) f3 (h z ) f4 ( k h z ) a1(db) a2(db) 34368 g. 8 2 3 etsi-tbr-24 100 300 3 k 800 k 0.5 -19.5 44736 gr-499, cat i gr-499, cat ii gr-253 core 10 10 10 10k 56.6k 40 - - - 15k 300k 15k 0.1 0.1 0.1 - - - 51840 gr-253 core 10 40k - 400k 0.1 - f igure 28. j itter t ransfer r equirements and j itter a ttenuator p erformance f1 a1 f2 jitter amplitude jitter frequency (khz) a2 f3 f4
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 38 5.0 diagnostic features 5.1 prbs generator and detector the XRT75L06 contains an on-chip pseudo random binary sequence (prbs) generator and detector for diagnostic purpose. with the prbsen_n bit = 1, the transmitter will send out prbs of 2 23 -1 in e3 rate or 2 15 -1 in sts-1/ds3 rate. at the same time, the receiver prbs detector is also enabled. when the correct prbs pattern is detected by the receiver, the rneg/lcv pin will go low to indicate prbs synchronization has been achieved. when the prbs detector is not in sync the prbsls bit will be set to 1 and rneg/lcv pin will go high. with the prbs mode enabled, the user can also insert a single bit error by toggling insprbs bit. this is done by writing a 1 to insprbs bit. the receiver at rneg/lcv pin will pulse high for one rxclk cycle for every bit error detected. any subsequent single bit error insertion must be done by first writing a 0 to insprbs bit and followed by a 1. figure 29 shows the status of rneg/lcv pin when the XRT75L06 is configured in prbs mode. n ote : in prbs mode, the device is forced to operate in single-rail mode. f igure 29. prbs mode rxclk rxneg/lcv sync loss prbs sync single bit error
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 39 5.2 loopbacks the XRT75L06 offers three loopback modes for diagnostic purposes. the loopback modes are selected via the rlb_n and llb_n bits n the channel control registers select the loopback modes. 5.2.1 analog loopback in this mode, the transmitter outputs ttip_n and tring_n are internally connected to the receiver inputs rtip_n and rring_n as shown in figure 30. data and clock are output at rxclk_n, rxpos_n and rxneg_n pins for the corresponding transceiver. analog loopback exercises most of the functional blocks of the device including the jitter attenuator which can be selected in either the transmit or receive path. n otes : 1. in the analog loopback mode, data is also output via ttip_n and tring_n pins. 2. signals on the rtip_n and rring_n pins are ignored during analog loopback. f igure 30. a nalog l oopback tring ttip rring rtip rxpos rxneg rxclk txneg txclk txpos hdb3/b3zs encoder hdb3/b3zs decoder jitter attenuator jitter attenuator timing control data & clock recovery tx rx
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 40 5.2.2 digital loopback when the digital loopback is selected, the transmit clock txclk_n and transmit data inputs (txpos_n & txneg_n are looped back and output onto the rxclk_n, rxpos_n and rxneg_n pins as shown in figure 31. 5.2.3 remote loopback with remote loopback activated as shown in figure 32, the receive data on rtip and rring is looped back after the jitter attenuator (if selected in receive or transmit path) to the transmit path using rxclk as transmit timing. the receive data is also output via the rxpos and rxneg pins. n ote : input signals on txclk, txpos and txneg are ignored during remote loopback. f igure 31. d igital l oopback f igure 32. r emote l oopback tring ttip rring rtip rxpos rxneg rxclk txneg txclk txpos hdb3/b3zs encoder hdb3/b3zs decoder jitter attenuator jitter attenuator timing control data & clock recovery tx rx tring ttip rring rtip rxpos rxneg rxclk txneg txclk txpos hdb3/b3zs encoder hdb3/b3zs decoder jitter attenuator jitter attenuator timing control data & clock recovery tx rx
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 41 5.3 transmit all ones (taos) transmit all ones (taos) can be set by setting the taos_n control bits to 1 in the channel control registers. when the taos is set, the transmit section generates and transmits a continuous ami all 1s pattern on ttip_n and tring_n pins. the frequency of this ones pattern is determined by txclk_n. the taos data path is shown in figure 33. taos does not operate in analog loopback or remote loopback modes, however will function in digital loopback mode. f igure 33. t ransmit a ll o nes (taos) tring ttip rring rtip rxpos rxneg rxclk txneg txclk txpos hdb3/b3zs encoder hdb3/b3zs decoder jitter attenuator jitter attenuator timing control data & clock recovery tx rx taos transmit all 1's
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 42 6.0 microprocessor interface block the microprocessor interface section supports communication between the local microprocessor (p) and the liu. the XRT75L06 supports a parallel interface asynchronously or synchronously timed to the liu. the mi- croprocessor interface is selected by the state of the pmode input pin. selecting the microprocessor interface mode is shown in table 11. the local p configures the liu by writing data into specific addressable, on-chip read/write registers. the p provides the signals which are required for a general purpose microprocessor to read or write data into these registers. the p also supports polled and interrupt driven environments. a simplified block diagram of the microprocessor is shown in figure 34. t able 11: s electing the m icroprocessor i nterface m ode p mode m icroprocessor m ode "low" asynchronous mode "high" synchronous mode f igure 34. s implified b lock d iagram of the m icroprocessor i nterface b lock microprocessor interface wr rd pmode rdy reset pclk cs int addr[7:0] d[7:0]
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 43 6.1 t he m icroprocessor i nterface b lock s ignals the liu may be configured into different operating modes and have its performance monitored by software through a standard microprocessor using data, address and control signals. these interface signals are de- scribed below in table 12. the microprocessor interface can be configured to operate in asynchronous mode or synchronous mode. t able 12: XRT75L06 m icroprocessor i nterface s ignals p in n ame t ype d escription pmode i microprocessor interface mode select input pin this pin is used to specify the microprocessor interface mode. d[7:0] i/o bi-directional data bus for register "read" or "write" operations. addr[7:0] i eight-bit address bus inputs the XRT75L06 liu microprocessor interface uses a direct address bus. this address bus is provided to permit the user to select an on-chip register for read/write access. cs i chip select input this active low signal selects the microprocessor interface of the XRT75L06 liu and enables read/write operations with the on-chip register locations. rd i read signal this active low input functions as the read signal from the local p. when this pin is pulled low (if cs is low) the liu is informed that a read operation has been requested and begins the process of the read cycle. wr i write signal this active low input functions as the write signal from the local p. when this pin is pulled low (if cs is low) the liu is informed that a write operation has been requested and begins the process of the write cycle. rdy o ready output this active low signal is provided by the liu device. it indicates that the cur- rent read or write cycle is complete, and the liu is waiting for the next command. int o interrupt output this active low signal is provided by the liu to alert the local mp that a change in alarm status has occured. this pin is reset upon read (rur) once the alarm sta- tus registers have been cleared. reset i reset input this active low input pin is used to reset the liu.
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 44 6.2 a synchronous and s ynchronous d escription whether the liu is configured for asynchronous or synchronous mode, the following descriptions apply. the synchronous mode requires an input clock (pclk) to be used as the microprocessor timing reference. read and write operations are described below. read cycle (for pmode = "0" or "1") whenever the local p wishes to read the contents of a register, it should do the following. 1. place the address of the target register on the address bus input pins addr[7:0]. 2. while the p is placing this address value on the address bus, the address decoding circuitry should assert the cs pin of the liu, by toggling it "low". this action enables communication between the p and the liu microprocessor interface block. 3. next, the p should indicate that this current bus cycle is a read operation by toggling the rd input pin "low". this action enables the bi-directional data bus output drivers of the liu. 4. after the p toggles the read signal "low", the liu will toggle the rdy output pin "low". the liu does this to inform the p that the data is available to be read by the p, and that it is ready for the next command. 5. after the p detects the rdy signal and has read the data, it can terminate the read cycle by toggling the rd input pin "high". 6. the cs input pin must be pulled "high" before a new command can be issued. write cycle (for pmode = "0" or "1") whenever a local p wishes to write a byte or word of data into a register within the liu, it should do the follow- ing. 1. place the address of the target register on the address bus input pins addr[7:0]. 2. while the p is placing this address value on the address bus, the address decoding circuitry should assert the cs pin of the liu, by toggling it "low". this action enables communication between the p and the liu microprocessor interface block. 3. the p should then place the byte or word that it intends to write into the target register, on the bi-direc- tional data bus d[7:0]. 4. next, the p should indicate that this current bus cycle is a write operation by toggling the wr input pin "low". this action enables the bi-directional data bus input drivers of the liu. 5. after the p toggles the write signal "low", the liu will toggle the rdy output pin "low". the liu does this to inform the p that the data has been written into the internal register location, and that it is ready for the next command. 6. the cs input pin must be pulled "high" before a new command can be issued.
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 45 t able 13: a synchronous t iming s pecifications f igure 35. a synchronous p i nterface s ignals d uring p rogrammed i/o r ead and w rite o perations s ymbol p arameter m in m ax u nits t 0 valid address to cs falling edge 0 - ns t 1 cs falling edge to rd assert 0 - ns t 2 rd assert to rdy assert - 65 ns na rd pulse width (t 2 )70-ns t 3 cs falling edge to wr assert 0 - ns t 4 wr assert to rdy assert - 65 ns na wr pulse width (t 4 )70-ns cs addr[7:0] d[7:0] rd wr rdy valid data for readback data available to write into the liu read operation write operation t 0 t 0 t 1 t 4 t 2 t 3 valid address valid address
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 46 f igure 36. s ynchronous p i nterface s ignals d uring p rogrammed i/o r ead and w rite o perations t able 14: s ynchronous t iming s pecifications n ote : 1. this timing parameter is based on the frequency of the synchronous clock (pclk). to determine the access time, use the following formula: (pclk period * 2) + 5ns s ymbol p arameter m in m ax u nits t 0 valid address to cs falling edge 0 - ns t 1 cs falling edge to rd assert 0 - ns t 2 rd assert to rdy assert - 35 ns, see note 1 na rd pulse width (t 2 )40-ns t 3 cs falling edge to wr assert 0 - ns t 4 wr assert to rdy assert - 35 ns, see note 1 na wr pulse width (t 4 )40-ns pclk period 15 ns pclk duty cycle pclk "high/low" time cs addr[7:0] d[7:0] rd wr rdy valid data for readback data available to write into the liu read operation write operation t 0 t 0 t 1 t 4 t 2 t 3 valid address valid address pclk
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 47 f igure 37. i nterrupt process error condition occurs interrupt enable bits at 0x60 and 0xn1 set? interrupt status bits at 0x61 and 0xn2 set. interrupt generated int pin goes "low" interrupt service routine reads the status register at 0x61 interrupt service routine reads the status register at 0xn2 interrupt is being serviced. interrupt pending ? int pin goes "high" normal operation yes yes no no
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 48 6.2.1 hardware reset: the hardware reset is initiated by pulling the reset pin low for a minimum of 5 m s. after the reset pin is released, the register values are put in default states. t able 15: r egister m ap and b it n ames a ddress (h ex ) p arameter n ame d ata b its 76543210 0x00 aps/redun- dancy #1 reserved txon_5 txon_4 txon_3 txon_2 txon-1 txon_0 0x08 aps/ redun- dancy #2 reserved rxon_5 rxon_4 rxon_3 rxon_2 rxon_1 rxon_0 0x60 interrupt enable (read/write) reserved inten_5 inten_4 inten_3 inten_2 inten_1 inten_0 0x61 interrupt status (read only) reserved intst_5 intst_4 intst_3 intst_2 intst_1 intst_0 0x62 - 0x6d reserved 0x6e chip_id (read only) 0x111110 0x6f chip_revision _id (read only) chip version number
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 49 t able 16: r egister m ap d escription - g lobal a ddress (h ex ) t ype r egister n ame s ymbol d escription d efault v alue 0x00 r/w aps # 1 txon_n table below shows the status of the transmitter based on the bit and pin setting. 0 0x08 r/w aps # 2 rxon_n set this bit to turn on individual receiver. 0 0x60 r/w interrupt enable inten_n set this bit to enable the interrupts on per channel basis. 0 0x61 ror interrupt status intst_n bits are set when an interrupt occurs.the respective source level interrupt status registers are read to determine the cause of interrupt. 0 0x62 - 0x6d reserved 0x6e r device _ id chip_id this read only register contains device id. 01110110 0x6f r version number chip_version this read only register contains chip version number t able 17: r egister m ap and b it n ames - c hannel n r egisters ( n = 0,1,2,3,4,5) a ddress (h ex ) p arameter n ame d ata b its 76 543210 0x01 (ch 0) 0x11 (ch 1) 0x21 (ch 2) 0x31 (ch 3) 0x41 (ch 4) 0x51 (ch 5) interrupt enable (read/write) reserved prbser cntie_n prbseri e_n flie_n rlolie_n rlosie_ n dmoie_n 0x02 (ch 0) 0x12 (ch 1) 0x22 (ch 2) 0x32 (ch 3) 0x42 (ch 4) ox52 (ch 5) interrupt status (reset on read) reserved prbser cntis_n prbseri s_n flis_n rlolis_n rlosis_ n dmois_n bit 0 0 transmitter status off off pin 0 1 1 1 off on 0 1
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 50 0x03 (ch 0) 0x13 (ch 1) 0x23 (ch 2) 0x33 (ch 3) 0x43 (ch 4) 0x53 (ch 5) alarm status (read only) reserved prbsls_n dlos_n alos_n fl_n rlol_n rlos_n dmo_n 0x04 (ch 0) 0x14 (ch 1) 0x24 (ch 2) 0x34 (ch 3) 0x44 (ch 4) 0x54 (ch 5) transmit control (read/write) reserved txmon_n insprbs _n reserved taos_n txclkinv _n txlev_n 0x05 (ch 0) 0x15 (ch 1) 0x25 (ch 2) 0x35 (ch 3) 0x45 (ch 4) 0x55 (ch 5) receive control (read/write) reserved dlosdis _n alosdis _n rxclkin v_n losmut_ n rxmon_n reqen_ n 0x06 (ch 0) 0x16 (ch 1) 0x26 (ch 2) 0x36 (ch 3) 0x46 (ch 4) 0x56 (ch 5) block control (read/write) reserved clkoute n_n prbsen_ 0 rlb_n llb_n e3_n sts1/ ds3 _n sr/dr _n 0x07 (ch 0) 0x17 (ch 1) 0x27 (ch 2) 0x37 (ch 3) 0x47 (ch 4) 0x57 (ch 5) jitter attenuator control (read/write) reserved dflck_n pntrst_ n ja1_n jatx/rx _n ja0_n 0x0a (ch 0) 0x1a (ch 1) 0x2a (ch 2) 0x3a (ch 3) 0x4a (ch 4) 0x5a (ch 5) prbs error count reg. msb bit 15 bit 14 bit 13 bit 12 bit 11 bit 10 bit 9 bit 8 0x0b (ch 0) 0x1b (ch 1) 0x2b (ch 2) 0x3b (ch 3) 0x4b (ch 4) 0x5b (ch 5) prbs error count reg. lsb bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 0x0c (ch 0) 0x1c (ch 1) 0x2c (ch 2) 0x3c (ch 3) 0x4c (ch 4) 0x5c (ch 5) prbs error count holding register t able 17: r egister m ap and b it n ames - c hannel n r egisters ( n = 0,1,2,3,4,5) a ddress (h ex ) p arameter n ame d ata b its 76 543210
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 51 t able 18: r egister m ap d escription - c hannel n a ddress (h ex ) t ype r egister n ame bit# s ymbol d escription d efault v alue 0x01 (ch 0) 0x11 (ch 1) 0x21 (ch 2) 0x31 (ch 3) 0x41 (ch 4) 0x51 (ch 5) r/w interrupt enable (source level) d0 dmoie_n if the driver monitor (connected to the output of the channel) detects the absence of pulses for 128 con- secutive cycles, it will set the interrupt flag if this bit has been set. 0 d1 rlosie_n this flag will allow a loss of receive signal(for that channel) to send an interrupt to the host when this bit is set. 0 d2 rlolie_n this flag will allow a loss of lock condition to send an interrupt to the host when this bit is set. 0 d3 flie_n set this bit to enable the interrupt when the fifo limit of the jitter attenuator is within 2 bits of over- flow/underflow condition. n ote : this bit field is ignored when the jitter atten- uator is disabled. 0 d4 prbserie _n set this bit to enable the interrupt when the prbs error is detected. 0 d5 prbserc ntie_n set this bit to enable the interrupt when the prbs error count register saturates. 0 d6-d7 reserved 0x02 (ch 0) 0x12 (ch 1) 0x22 (ch 2) 0x32 (ch 3) 0x42 (ch 4) 0x52 (ch 5) reset on read interrupt status (source level) d0 dmois_n if the drive monitor circuot detects the absence of pulses for 128 consecutive cycles, t will set this interrupt status flag (if enabled) this bit is set on a change of state of the dmo circuit. 0 d1 rlosis_n this flag will indicate a change of loss of receive signal to the host when this bit is set. 0 d2 rlolis_n this flag will allow a change in the loss of lock condi- tion to send an interrupt to the host when this bit is enabled.loss of lock is defined as a difference of greater than 0.5% between the recovered clock and the channels reference clock. any change (return to lock) will trigger the interrupt status flag again. 0 d3 flis_n this bit will generate an interrupt if the jitter attenua- tor fifo reaches (or leaves) a limit condition. this limit condition is defined as the fifo being within two counts of full or empty. 0 d4 prbseris _n this bit is set when the prbs error occurs. 0 d5 prbserc ntis_n this bit is set when the prbs error count register saturates. 0 d7-d6 reserved
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 52 0x03 (ch 0) 0x13 (ch 1) 0x23 (ch 2) 0x33 (ch 3) 0x43 (ch 4) 0x53 (ch 5) read only alarm sta- tus d0 dmo_n this bit is set when no transitions on the ttip/ tring have been detected for 128 32 txclk periods.it will be cleared when pulses resume. 0 d1 rlos_n this bit is set every time the receiver declares an los condition.it will be cleared when the signal is recognized again. 0 d2 rlol_n this bit is set when the detected clock is greater than 0.5% oof frequency from the reference clock.by definition, the two frequencies are not in lock with each other. it will be cleared when they are in lock again.. 0 d3 fl_n this bit is set when the fifo reaches its limit.the limit is defined to be within two bits of either under- flow or overflow. 0 d4 alos_n this bit is set when the receiver declares that the analog signal has degraded to the point that the sig- nal has been lost. 0 d5 dlos_n this bit is set when no input signals have been received for 10 to 255 bit times in e3 or 100 to 250 bit times in ds3 or sts-1 modes.this is a complete lack of incoming pulses rather than signal attenua- tion (alos). it should be noted that this time period is built into the analog detector for e3 mode. even though ds3/sts-1 mode does not require analog detection level, but it is provided and could help to determine the quality of the line for ds/sts-1 applications. 0 d6 prbsls_n this bit is set when the prbs detector has been enabled and it is not in sync with the incoming data pattern. once the sync is achieved, it will be cleared. 0 d7 reserved t able 18: r egister m ap d escription - c hannel n a ddress (h ex ) t ype r egister n ame bit# s ymbol d escription d efault v alue
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 53 0x04 (ch 0) 0x14 (ch 1) 0x24 (ch 2) 0x34 (ch 3) 0x44 (ch 4) 0x54 (ch 5) r/w transmit control d0 txlev_n this bit should be set when the transmitter is driving a line greater than 225 feet in the ds3 or sts-1 modes. it is not active in e3 mode. 0 d1 txclkinv _n set this bit to sample the data on tpos/tneg pins on the rising edge of txclk.default is to sample on the falling edge of txclk. 0 d2 taos_n this bit should be set to transmit a continuous all ones data pattern. timing will come from txclk if available otherwise from channel refernce clock. 0 d3 reserved d4 insprbs_ n this bit causes a single bit error to be inserted in the transmitted prbs pattern if the prbs generator/ detector has been enabled. 0 d5 txmon_n when set, this bit enables the dmo circuit to moni- tor its own channels transmit driver. otherwise, it uses the mtip/mring pins to monitor another channel or device. 0 d7-d6 reserved 0x05 (ch 0) 0x15 (ch 1) 0x25 (ch 2) 0x35 (ch 3) 0x45 (ch 4) 0x55 (ch 5) r/w receive control d0 reqen_n this bit enables the receiver equalizer. when set, the equalizer boosts the high frequency components of the signal to make up for cable losses. n ote : see section 5.01 for detailed description. 0 d1 rxmon_n set this bit to place the receiver in the monitoring mode. in this mode, it can process signals (at rtip/ rring) with 20db of flat loss. this mode allows the channel to act as monitor of aline without loading the circuit. 0 d2 losmut_ n when set, the data on rpos/rneg is forced to zero when los occurs. thus any residual noise on the line is not output as spurious data. n ote : if this bit has been set, it will remain set evan after the los condition is cleared. 0 d3 rxclkinv _n when this bit is set, rpos and rneg will change on the falling edge of rclk.default is for the data to change on the rising edge of rclk and be sampled by the terminal equipment on the falling edge of rclk. 0 d4 alosdis_ n this bit is set to disable the alos detector. this flag and the dlosdis are normally used in diagnostic mode. normal operation of ds3 and sts-1 would have alos disabled. 0 d5 dlosdis_ n this bit disables the digital los detector. this would normally be disabled in e3 mode as e3 is a function of the level of the input. 0 d7-d6 reserved t able 18: r egister m ap d escription - c hannel n a ddress (h ex ) t ype r egister n ame bit# s ymbol d escription d efault v alue
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 54 0x06 (ch 0) 0x16 (ch 1) 0x26 (ch 2) 0x36 (ch 3) 0x46 (ch 4) 0x56 (ch 5) r/w block con- trol d0 sr/dr _n setting this bit configures the receiver and trans- mitter in single-rail (nrz) mode. n ote : see section 4.0 for detailed description. 0 d1 sts-1/ ds3 _n setting this bit configures the channel into sts-1 mode. n ote : this bit field is ignored if the channel is con- figured to operate in e3 mode. 0 d2 e3_n setting this bit configures the channel in e3 mode. 0 d3 llb_n setting this bit configures the channel in local loop- back mode. 0 d4 rlb_n this bit along with llb_n determine the diagnostic mode as shown in the table below. 0 d5 prbsen_ n setting this bit enables the prbs generator/detec- tor. when in e3 mode, an unframed 2 23 -1 pattern is used. for ds3 and sts-1, unframed 2 15 -1 pattern is used. this mode of operation will use tclk for tim- ing. one should insure that a stable frequency is provided. looping this signal back to its own receive channel and using rclk to generate tclk will cause an unstable condition and should be avoided. 0 d6 clkoute n_n set this bit to enable the clkouts on a per channel basis. the frequency of the output clock is depen- dent on the configuration of the channels, either e3, ds3 or sts-1. 0 d7 reserved t able 18: r egister m ap d escription - c hannel n a ddress (h ex ) t ype r egister n ame bit# s ymbol d escription d efault v alue rlb_n 0 0 loopback mode normal operation analog local llb_n 0 1 1 1 remote digital 0 1
XRT75L06 rev. 1.0.2 six channel e3/ds3/sts-1 line interface unit with jitter attenuator 55 0x07 (ch 0) 0x17 (ch 1) 0x27 (ch 2) 0x37 (ch 3) 0x47 (ch 4) 0x57 (ch 5) r/w jitter attenuator d0 ja0_n this bit along with ja1_n bit configures the jitter attenuator as shown in the table below. 0 d1 jatx/rx _n setting this bit selects the jitter attenuator in the transmit path. a 0 selects in the receive path. 0 d2 ja1_n this bit along with the ja0_n configures the jitter attenuator as shown in the table. 0 d3 pntrst_n setting this bit resets the fifo pointers to their initial state and flushes the fifo. all existing fifo data is lost. 0 d4 dflck_n set this bit to 1 to disable fast locking of the pll. this helps to reduce the time for the pll to lock to incoming frequency when the jitter attenuator switches to narrow band. 0 d7-d5 reserved t able 18: r egister m ap d escription - c hannel n a ddress (h ex ) t ype r egister n ame bit# s ymbol d escription d efault v alue ja0_n 0 0 mode 16 bit fifo 32 bit fifo ja1_n 0 1 1 1 disable jitter attenuator 0 1 disable jitter attenuator
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 56 7.0 electrical characteristics n otes : 1. exposure to or operating near the min or max values for extended period may cause permanent failure and impair reliability of the device. 2. esd testing method is per mil-std-883d,m-3015.7 3. with linear air flow of 200 ft/min, reduce theta ja by 20%, theta jc is unchanged. n otes : 1. not applicable for pins with pull-up or pull-down resistors. 2. the digital inputs are ttl 5v compliant. t able 19: a bsolute m aximum r atings symbol p arameter min max units comments v dd supply voltage -0.5 6.0 v note 1 v in input voltage at any pin -0.5 5.5 v note 1 i in input current at any pin 100 ma note 1 s temp storage temperature -65 150 0 c note 1 a temp ambient operating temperature -40 85 0 c linear airflow 0 ft./min theta ja thermal resistance 23 0 c/w linear air flow 0ft/min (see note 3 below) m levl exposure to moisture 5 level eia/jedec jesd22-a112-a esd esd rating 2000 v note 2 t able 20: dc e lectrical c haracteristics : symbol p arameter min . typ . max . units dv dd digital supply voltage 3.135 3.3 3.465 v av dd analog supply voltage 3.135 3.3 3.465 v i cc supply current requirements tbd tbd ma p dd power dissipation tbd tbd w v il input low voltage 0.8 v v ih input high voltage 2.0 5.5 v v ol output low voltage, i out = - 4ma 0.4 v v oh output high voltage, i out = 4 ma 2.4 v i l input leakage current 1 10 m a c i input capacitance 10 pf c l load capacitance 10 pf
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 57 appendix a transformer vendor information pulse corporate office 12220 world trade drive san diego, ca 92128 tel: (858)-674-8100 fax: (858)-674-8262 europe 1 & 2 huxley road the surrey research park guildford, surrey gu2 5re united kingdom tel: 44-1483-401700 fax: 44-1483-401701 t able 21: transformer recommendations p arameter v alue turns ratio 1:1 primary inductance 40 m h isolation voltage 1500 vrms leakage inductance 0.6 m h t able 22: t ransformer d etails p art n umber v endor i nsulation p ackage t ype pe-68629 pulse 3000 v large thru-hole pe-65966 pulse 1500 v small thru-hole pe-65967 pulse 1500 v smt t 3001 pulse 1500 v smt tg01-0406ns halo 1500 v smt tti 7601-sm transpower 1500 v smt
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 58 asia 150 kampong ampat #07-01/02 ka centre singapore 368324 tel: 65-287-8998 website: http://www.pulseeng.com halo electronics corporate office p.o. box 5826 redwood city, ca 94063 tel: (650)568-5800 fax: (650)568-6165 email: info@haloelectronics.com website: http://www.haloelectronics.com transpower technologies, inc. corporate office park center west building 9805 double r blvd, suite # 100 reno, nv 89511 (800)500-5930 or (775)852-0140 email: info@trans-power.com website: http://www.trans-power.com
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 59 ordering information p art n umber p ackage o perating t emperature r ange XRT75L06ib 217 lead bga (23 x 23 mm) - 40 c to + 85 c package dimensions - 23 x 23 mm 217 lead bga package symbol min max min max a 0.067 0.098 1.70 2.50 a1 0.016 0.028 0.40 0.70 a2 0.012 0.024 0.30 0.60 a3 0.039 0.047 1.00 1.20 d 0.898 0.913 22.80 23.20 d1 0.800 bsc 20.32 bsc d2 0.780 0.795 19.80 20.20 b 0.024 0.035 0.60 0.90 e 0.050 bsc 1.27 bsc b 10 20 10 20 i nches mi lli meters note: the control dimension is in millimeter. bottom view (a1 corner feature is mfger option) b
XRT75L06 six channel e3/ds3/sts-1 line interface unit with jitter attenuator rev. 1.0.2 60 notice exar corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. exar corporation assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no represen- tation that the circuits are free of patent infringement. charts and schedules contained here in are only for illustration purposes and may vary depending upon a users specific application. while the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. exar corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support sys- tem or to significantly affect its safety or effectiveness. products are not authorized for use in such applica- tions unless exar corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; (c) potential liability of exar corpo- ration is adequately protected under the circumstances. copyright 2003 exar corporation datasheet october 2003. reproduction, in part or whole, without the prior written consent of exar corporation is prohibited. revisions r evision d ate c omments p1.0.0 original p1.0.2 renamed the pins dja and fss. included the clock out and clock enable func- tion for the single frequency mode. p1.0.3 changed the txon pin from internal pull down to pull up.changed the operation of txon in host mode.included internal monitoring feature. p1.0.4 losmut bit operation description was changed. 1.0.1 06/03 removed the tqfp package information since no longer offered in tqfp. 1.0.2 10/30 re-arranged the datasheet and finalized the electrical specifications.

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