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MT88E45
4-Wire Calling Number Identification Circuit 2 Advance Information
Features
* Compatible with: * Bellcore GR-30-CORE, SR-TSV-002476, ANSI/TIA/EIA-716, draft TIA/EIA-777; * ETSI ETS 300 778-1 (FSK only variant) & -2; * BT (British Telecom) SIN227 & SIN242 Bellcore `CPE Alerting Signal' (CAS), ETSI `Dual Tone Alerting Signal' (DT-AS), BT Idle State and Loop State `Tone Alert Signal' detection 1200 baud Bell 202 and CCITT V.23 FSK demodulation Separate differential input amplifiers with adjustable gain for Tip/Ring and telephone hybrid or speech IC connections Selectable 3-wire FSK data interface (bit stream or 1 byte buffer) Facility to monitor the stop bit for framing error check FSK Carrier detect status output 3 to 5V +/- 10% supply voltage Uses 3.579545MHz crystal or ceramic resonator Low power CMOS with power down Bellcore CID (Calling Identity Delivery) and CIDCW (Calling Identity Delivery on Call Waiting) telephones and adjuncts ETSI, BT CLIP (Calling Line Identity Presentation) and CLIP with Call Waiting telephones and adjuncts Fax and answering machines Computer Telephony Integration (CTI) systems
FSKen+Tip/Ring CASen IN1+ IN1GS1
PWDN
(4-Wire CNIC2)
ISSUE 2 March 1999
DS5143
Ordering Information MT88E45AS 20 Pin SOIC -40C to 85C
*
Description
The MT88E45 is a low power CMOS integrated circuit suitable for receiving the physical layer signals used in North American (Bellcore) Calling Identity Delivery on Call Waiting (CIDCW) and Calling Identity Delivery (CID) services. It is also suitable for ETSI and BT Calling Line Identity Presentation (CLIP) and CLIP with Call Waiting services. The MT88E45 contains a 1200 baud Bell 202/CCITT V.23 FSK demodulator and a CAS/DT-AS detector. Two input op-amps allow the MT88E45 to be connected to both Tip/Ring and the telephone hybrid or speech IC receive pair for optimal CIDCW telephone architectural implementation. FSK demodulation is always on Tip/Ring, while CAS detection can be on Tip/Ring or Hybrid Receive. Tip/ Ring CAS detection is required for Bellcore's proposed Multiple Extension Interworking (MEI) and BT's on-hook CLIP. A selectable FSK data interface allows the data to be processed as a bit stream or extracted from a 1 byte on chip buffer. Power management has been incorporated to power down the FSK or CAS section when not required. Full chip power down is also available. The MT88E45 is suitable for applications using a fixed power source (with a +/-10% variation) between 3 and 5V.
* *
* * * * * * *
Applications
*
* *
MODE FSK Bandpass FSKen CASen Mux Carrier Detector DR STD Tone Detection Algorithm Guard Time FSK Demodulator Data Timing Recovery DATA DCLK
+ PWDN
Anti-Alias Filter PWDN
CD DR/STD
IN2+ IN2GS2 VREF
+ Hybrid CASen
MODE PWDN CASen
2130Hz Bandpass 2750Hz Bandpass
Bias Generator PWDN Oscillator
FSKen
ST/GT EST Vdd Vss
Control Bit Decode
CASen OSC1 OSC2 CB0 CB1 CB2
Figure 1 - Functional Block Diagram
1
MT88E45
VREF IN1+ IN1GS1 Vss OSC1 OSC2 CB0 DCLK DATA 1 2 3 4 5 6 7 8 9 10 MT88E45 20 19 18 17 16 15 14 13 12 11 IN2+ IN2GS2 CB2 CB1 Vdd CD ST/GT EST DR/STD
Advance Information
Figure 2 - Pin Connections
Pin Description
Pin # Name 1 2 3 4 VREF IN1+ IN1GS1 Description Voltage Reference (Output). Nominally Vdd/2. It is used to bias the Tip/Ring and Hybrid input op-amps. Tip/Ring Op-amp Non-inverting (Input). Tip/Ring Op-amp Inverting (Input). Tip/Ring Gain Select (Output). This is the output of the Tip/Ring connection op-amp. The opamp should be used to connect the MT88E45 to Tip and Ring. The Tip/Ring signal can be amplified or attenuated at GS1 via selection of the feedback resistor between GS1 and IN1-. FSK demodulation (which is always on Tip/Ring) or CAS detection (for MEI or BT on-hook CLIP) of the GS1 signal is enabled via the CB1 and CB2 pins. See Tables 1 and 2. Power supply ground.
5 6 7 8
Vss
OSC1 Oscillator (Input). Crystal connection. This pin can also be driven directly from an external clock source. OSC2 Oscillator (Output). Crystal connection. When OSC1 is driven by an external clock, this pin should be left open. CB0 Control Bit 0 (CMOS Input). This pin is used primarily to select the 3-wire FSK data interface mode. When it is low, interface mode 0 is selected where the FSK bit stream is output directly. When it is high, interface mode 1 is selected where the FSK byte is stored in a 1 byte buffer which can be read serially by the application's microcontroller. The FSK interface is consisted of the DATA, DCLK and DR/STD pins. See the 3 pin descriptions to understand how CB0 affects the FSK interface. When CB0 is high and CB1, CB2 are both low the MT88E45 is put into a power down state consuming minimal power supply current. See Tables 1 and 2.
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DCLK 3-wire FSK Interface Data Clock (Schmitt Input/CMOS Output). In mode 0 (when the CB0 pin is logic low) this is a CMOS output which denotes the nominal mid-point of a FSK data bit. In mode 1 (when the CB0 pin is logic high) this is a Schmitt trigger input used to shift the FSK data byte out to the DATA pin.
2
Advance Information
Pin Description
Pin # Name 10 DATA Description
MT88E45
3-wire FSK Interface Data (CMOS Output). Mark frequency corresponds to logical 1. Space frequency corresponds to logical 0. In mode 0 (when the CB0 pin is logic low) the FSK serial bit stream is output to the DATA pin directly. In mode 1 (when the CB0 pin is logic high) the start bit is stripped off, the data byte and the trailing stop bit are stored in a 9 bit buffer. At the end of each word signalled by the DR/STD pin, the microcontroller should shift the byte out onto the DATA pin by applying 8 read pulses to the DCLK pin. A 9th DCLK pulse will shift out the stop bit for framing error checking.
11
DR/STD 3-wire FSK Interface Data Ready/CAS Detection Delayed Steering (CMOS Output). Active low. When FSK demodulation is enabled via the CB1 and CB2 pins this pin is the Data Ready output. It denotes the end of a word. In both FSK interface modes 0 and 1, it is normally hi and goes low for half a bit time at the end of a word. But in mode 1 if DCLK starts during DR low, the first rising edge of the DCLK input will return DR to high. This feature allows an interrupt requested by a low going DR to be cleared upon reading the first DATA bit. When CAS detection is enabled via the CB1 and CB2 pins this pin is the Delayed Steering output. It goes low to indicate that a time qualified CAS has been detected. EST CAS Detection Early Steering (CMOS Output). Active high. This pin is the raw CAS detection output. It goes high to indicate the presence of a signal meeting the CAS accept frequencies and signal level. It is used in conjunction with the ST/GT pin and external components to time qualify the detection to determine whether the signal is a real CAS.
12
13
ST/GT CAS Detection Steering/Guard Time (CMOS Output/Analog Input). It is used in conjunction with the EST pin and external components to time qualify the detection to determine whether the signal is a real CAS. A voltage greater than VTGt at this pin causes the MT88E45 to indicate that a CAS has been detected by asserting the DR/STD pin low. A voltage less than VTGt frees up the MT88E45 to accept a new CAS and returns DR/STD to high. CD Carrier Detect (CMOS Output). Active low. A logic low indicates that an FSK signal is present. A time hysteresis is provided to allow for momentary signal discontinuity. The demodulated FSK data is inhibited until carrier detect has been activated. Positive power supply. Control Bit 1 (CMOS Input). Together with CB2 this pin selects the MT88E45's functionality between FSK demodulation, Tip/Ring CAS detection and Hybrid CAS detection. When CB0 is high and CB1, CB2 are both low the MT88E45 is put into a power down state consuming minimal power supply current. See Tables 1 and 2. Control Bit 2 (CMOS Input). Together with CB1 this pin selects the MT88E45's functionality between FSK demodulation, Tip/Ring CAS detection and Hybrid CAS detection. When CB0 is high and CB1, CB2 are both low the MT88E45 is put into a power down state consuming minimal power supply current. See Tables 1 and 2. Hybrid Gain Select (Output). This is the output of the hybrid receive connection op-amp. The opamp should be used to connect the MT88E45 to the telephone hybrid or speech IC receive pair. The hybrid receive signal can be amplified or attenuated at GS2 via selection of the feedback resistor between GS2 and IN2-. When the CPE is off-hook CAS detection of the GS2 signal should be enabled via the CB1 and CB2 pins. See Tables 1 and 2. Hybrid Op-amp Inverting (Input). Hybrid Op-amp Non-Inverting (Input).
14
15 16
Vdd CB1
17
CB2
18
GS2
19 20
IN2IN2+
3
MT88E45
CB0 CB1 CB2 0/1 0/1 0/1 1 1 0 1 0 1 FSK Interface Function
Advance Information
Set by CB0 FSK Demodulation. Tip/Ring input (GS1) selected. DR/STD is DR. Set by CB0 Hybrid CAS Detection. Hybrid Receive input (GS2) selected. DR/STD is STD. Set by CB0 Tip/Ring CAS Detection. Tip/Ring input (GS1) selected. DR/STD is STD. When the line is off-hook, a Bellcore Multiple Extension Interworking (MEI) compatible Type 2 CPE should be able to detect CAS from Tip/Ring while the CPE is on-hook because it may be the ACK sender. Tip/Ring CAS detection is also required for BT's on-hook CLIP. Mode 1 Mode 0 Power Down. The MT88E45 is disabled and draws virtually no power supply current. Reserved for factory testing.
1 0
0 0
0 0
Table 1 - CB0/1/2 Functionality The number of control bits (CB) required to interface the MT88E45 with the microcontroller depends on the functionality of the application, as shown in Table 2. Functionality Group FSK (mode 0 or 1) and Hybrid CAS only (Non MEI compatible) Controls CB2 Description CB0 is hardwired to Vdd or Vss to select the FSK interface. CB1 hardwired to Vdd. The microcontroller uses CB2 to select between the 2 functions. CB0 is hardwired to Vdd or Vss to select the FSK interface. The microcontroller uses CB1 and CB2 to select between the 3 functions. CB0 is hardwired to Vdd to select FSK interface mode 1. The microcontroller uses CB1 and CB2 to select between the 4 functions.
FSK (mode 0 or 1), Hybrid CAS, Tip/Ring CAS (MEI compatible or BT on-hook CLIP) FSK (mode 1), Hybrid CAS, Tip/Ring CAS, Power Down (MEI compatible or BT on-hook CLIP) FSK (mode 0), Hybrid CAS, Tip/Ring CAS, Power Down (MEI compatible or BT on-hook CLIP)
CB1 CB2
CB1 CB2
CB0 CB1 CB2
All 3 pins are required.
Table 2 - Control Bit Functionality Groups
Functional Overview
The MT88E45 is compatible with FSK and FSK plus CAS (CPE Alerting Signal) based Caller ID services around the world. Caller ID is the generic name for a group of services offered by telephone operating companies whereby information about the calling party is delivered to the subscriber. In Europe and some other countries Caller ID is known as Calling Line Identity Presentation (CLIP). ETSI calls CAS `Dual Tone Alerting Signal' (DT-AS), BT calls it `Tone Alert Signal'. Depending on the service, data delivery can occur when the line is in the on-hook or off-hook state. In
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most countries the data is modulated in either Bell 202 or CCITT V.23 FSK format and transmitted at 1200 baud from the serving end office to the subscriber's terminal. Additionally in off-hook signalling, the special dual tone CAS is used to alert the terminal before FSK data transmission. BT uses CAS to alert the terminal prior to FSK in both onhook (Idle State) and off-hook (Loop State) signalling. In North America, Caller ID uses the voiceband data transmission interface defined in the Bellcore document GR-30-CORE. The terminal or CPE (Customer Premises Equipment) requirements are defined in Bellcore document SR-TSV-002476. Typical services are CND (Calling Number Delivery),
Advance Information
CNAM (Calling Name Delivery), VMWI (Visual Message Waiting Indicator) and CIDCW (Calling Identity Delivery on Call Waiting). In Europe, Caller ID requirements are defined by ETSI. The CPE documents are ETS 300 778-1 for on-hook, ETS 300 778-2 for off-hook. The end office requirements are ETS 300 659-1 (on-hook) and ETS 300 659-2 (off-hook). ETSI has defined services such as CLIP and CLIP with Call Waiting which are similar to those of Bellcore. Some European countries produce their own national specifications. For example, in the UK BT's standards are SIN227 and SIN242, the UK CCA (Cable Communications Association) standard is TW/P&E/312. In on-hook Caller ID, such as CND, CNAM and CLIP, the information is typically transmitted (in FSK) from the end office before the subscriber picks up the phone. There are various methods such as between the first and second rings (North America), between an abbreviated ring and the first true ring (Japan, France and Germany). On-hook Caller ID can also occur without ringing for services such as VMWI. In BT's on-hook CLIP, the signalling begins with a line polarity reversal, followed by CAS and then FSK. Bellcore calls an on-hook capable Caller ID CPE a `Type 1 CPE'. In off-hook Caller ID, such as CIDCW and CLIP with Call Waiting, information about a new calling party is sent to the subscriber who is already engaged in a call. Bellcore's method uses CAS to alert the CPE. When the CPE detects CAS and there are no offhook extensions, the CPE should mute its transmission path and send an acknowledgment to the end office via a DTMF digit called ACK. Upon receiving ACK, the end office will send the FSK data. Bellcore calls an off-hook capable CPE a `Type 2 CPE'. A Type 2 CPE is capable of off-hook and Type 1 functionalities and should ACK with a DTMF `D'. The ETSI and BT off-hook signalling protocols are similar to Bellcore's but with timing and signal parametric differences. ETSI has no requirement for off-hook extension checking before ACK. One factor affecting the quality of the CIDCW service is the CPE's CAS speech immunity. Although the end office has muted the far end party before and after it sends CAS, the near end (the end which is to receive the information) user may be still talking. Therefore the CPE must be able to detect CAS successfully in the presence of near end speech. This is called the talkdown immunity. The CPE must also be immune to imitation of CAS by speech from both ends of the connection because the CAS detector is continuously exposed to speech throughout the call. This is called the talkoff immunity.
MT88E45
If the CPE is a telephone, one way to achieve good CAS speech immunity is to put CAS detection on the telephone hybrid or speech IC receive pair instead of on Tip and Ring. Talkdown immunity improves because the near end speech has been attenuated while the CAS level is the same as on Tip/Ring, resulting in improved signal to speech ratio. Talkoff immunity is also improved because the near end speech has been attenuated. In the present Bellcore off-hook protocol, the CPE should not ACK if it detected an off-hook extension. The FSK will not be sent and the customer will not receive a paid for service. Bellcore, in conjunction with the TIA (Telecommunications Industry Association) TR41.3.1 working group, has defined a CPE capability called Multiple Extension Interworking (MEI) which will overcome this problem. In the MEI scheme, all MEI compatible CPE's must be capable of detecting CAS when the line is offhook, even though the CPE itself may be on-hook. This is because under some conditions an on-hook CPE may become the ACK sender. Another reason for the on-hook CPE to detect CAS is to maintain synchronous call logs between on and off-hook CPEs. When CAS is received and all off-hook CPEs are MEI compatible, one of the CPEs will ACK and all compatible sets will receive FSK. A problem arises in a CPE where the CAS detector is connected only to the hybrid or speech IC receive pair: it cannot detect CAS when it is on-hook. The reason is that when the CPE is on-hook either the hybrid/speech IC is non functional or the signal level is severely attenuated. Therefore an on-hook Type 2 CPE must be capable of detecting CAS from Tip/ Ring, in addition to detecting CAS from the hybrid/ speech IC receive signal when it is off-hook. The MT88E45 offers an optimal solution which combines good speech immunity and MEI compatibility. Two input op-amps allow the MT88E45 to be connected both to Tip/Ring and to the hybrid/ speech IC receive pair. Both connections can be differential or single ended. FSK demodulation is always on the Tip/Ring signal. CAS detection can be from the Tip/Ring or hybrid/speech IC receive signal. Being able to detect CAS on Tip/Ring also makes the MT88E45 suitable for BT on-hook CLIP applications. For applications such as those in most European countries where Tip/Ring CAS detection is not needed, then the Tip/Ring and Hybrid op-amp gains can be tailored independently to meet country specific FSK and CAS signal level requirements respectively. Note that since the Hybrid op-amp is for
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MT88E45
CAS detection only, its gain can always be tailored specifically for the CAS signal level. The FSK demodulator is compatible with Bellcore, ETSI and BT standards. The demodulated FSK data is either output directly (bit stream mode) or stored in a one byte buffer (buffer mode). In the buffer mode, the stop bit immediately following a byte is also stored and can be shifted out after the data byte. This facility allows for framing error checking required in Type 2 CPEs. In the bit stream mode, two timing signals are provided. One indicates the bit sampling instants of the data byte, the other the end of byte. A carrier detector indicates presence of signal and shuts off the data stream when there is no signal. The entire chip can be put into a virtually zero current power down mode. The input op-amps, FSK demodulator, CAS detector and the oscillator are all shut off. Furthermore, power management has been incorporated to minimize operating current. When FSK is selected the CAS detector is powered down. When CAS is selected the FSK demodulator is powered down.
Advance Information
hook CLIP, while Hybrid CAS detection is needed for optimal CAS speech immunity. The feedback resistor connected between GS1 and IN1- can be used to adjust the Tip/Ring signal gain. The feedback resistor connected between GS2 and IN2- can be used to adjust the hybrid receive signal gain. When the Tip/Ring op-amp is selected, the GS2 signal is ignored. When the Hybrid op-amp is selected, the GS1 signal is ignored. Either or both op-amps can be configured in the single ended input configuration shown in Figure 3, or in the differential input configuration shown in Figure 4.
IN+
C
RIN
IN-
Voltage Gain (AV) = RF / RIN Highpass Corner Frequency f-3dB = 1/(2RINC)
RF
GS
VREF
Functional Description
3 to 5V Operation
Figure 3 - Single Ended Input Configuration
C1
R1
IN+ IN-
The MT88E45's FSK and CAS reject levels are proportional to Vdd. When operated at Vdd equal 3V +/- 10%, to keep the FSK and CAS reject levels as at 5V (nominal) the Tip/Ring and Hybrid op-amp gains should be reduced from those of 5V. Gains for nominal Vdd (with a +/- 10% variation) other than 3 or 5V can be chosen as interpolation between the 3 and 5V settings. Input Configuration The MT88E45 provides an input arrangement comprised of two op-amps and a bias source (VREF). VREF is a low impedance voltage source which is used to bias the op-amp inputs at Vdd/2. The Tip/ Ring op-amp (IN1+, IN1-, GS1 pins) is for connecting to Tip and Ring. The Hybrid op-amp (IN2+, IN2-, GS2 pins) is for connecting to the telephone hybrid or speech IC receive pair. Either FSK or CAS detection can be selected for the Tip/Ring connection, while the hybrid connection is for CAS detection only. Phrased in another way, FSK demodulation is always on Tip/Ring, while CAS detection can be on Tip/Ring or Hybrid Receive. Tip/ Ring CAS detection is required for MEI and BT on6
C2
R4
R5 GS R3 R2
VREF
Differential Input Amplifier C1 = C2 R1 = R4 (For unity gain R5= R4) R3 = (R2R5) / (R2 + R5) Voltage Gain Highpass Corner Frequency (AVdiff) = R5/R1 f-3dB = 1/(2R1C1) Input Impedance (ZINdiff) = 2 R12 + (1/C)2
Figure 4 - Differential Input Configuration CAS Detection In North America, CAS is used in off-hook signalling only. In Europe (ETSI) it is used in off-hook signalling, and by BT in both on and off-hook signalling. ETSI calls it the Dual Tone Alerting Signal (DT-AS). Although the ETSI on-hook standard contains a DT-AS specification, BT is the only administration known to employ CAS in on-hook
Advance Information
MT88E45
Bellcorea (Off-hook only) +/-0.5% -14 to -32 dBmd -45 dBm +/-6 dB 75 to 85 ms +/-6 dB 75 to 85 ms ETSIb (Off-hook) +/-0.5% -9.78 to -32.78 dBm (-12 to -35 dBVe) BTc (Off-hook = `Loop State') (On-hook = `Idle State') Off-hook: +/-0.6% On-hook: +/-1.1% +0.22 to -37.78 dBm (-2 to -40 dBV) On-hook: -43.78 dBm (-46 dBV) +/-7 dB Off-hook: 80 to 85 ms On-hook: 88 to 110 ms Off-hook: <=70 ms On-hook: <=20 ms Speech Speech Off-hook: Speech On-hook: >= 20 dB (300-3400 Hz) 0 dB TBD
2130 Hz and 2750 Hz CAS/DT-AS Characteristics Frequency Tolerance Signal Level (per tone) Reject Level (per tone) Maximum Twist (V2130Hz/V2750Hz) Duration Reject Duration Signal to Noise Ratio
Hybrid Op-amp (GS2) Gain Vdd = 5V +/- 10% Hybrid Op-amp (GS2) Gain Vdd = 3V +/- 10%
0 dB -3.5 dB
0 dB -3.5dB
a. SR-TSV-002476, Issue 1 Dec 1992 b. ETS 300 778-2 Jan 98. The DT-AS plus FSK variant of ETSI on-hook signalling described in ETS 300 778-1 is not supported because on-hook DT-AS uses the GS1 op-amp. With the GS1 gain in Table 4, the minimum DT-AS level will be below the MT88E45's minimum accept level. c. SIN227 Issue 3 Nov 97, SIN242 Issue 2 Nov 96 d. dBm - Decibels above or below a reference power of 1 mW into 600 ohms. 0 dBm = 0.7746 Vrms. e. dBV - Decibels above or below a reference voltage of 1 Vrms. 0 dBV = 1 Vrms
Table 3 - CAS/DT-AS Characteristics signalling. (BT calls it Tone Alert Signal.) The CAS/ DT-AS characteristics are summarized in Table 3. Table 3 shows the Hybrid op-amp gain for operation at 3V and 5V nominal Vdd, with a 10% Vdd variation. For 3V operation, the Hybrid op-amp gain should be reduced from the 5V setting to maintain the CAS reject level and to maintain the talkoff immunity: the CAS threshold is directly proportional to Vdd, when Vdd is reduced the threshold becomes lower, hence lower level CAS are accepted. If the gain is not reduced, the MT88E45 will be more talkoff prone. When CAS detection is selected, the dual purpose output pin DR/STD is STD. STD goes low when CAS has been detected, and returns high after CAS has ended. CAS Guard Time The guard time circuit shown in Figure 5 implements a timing algorithm which determines whether the signal is a CAS. Proper selection of the guard time(s) is key to good speech immunity. The first indication that there might be a CAS is when EST goes high. EST high indicates that both tones are present. EST low indicates that one or both tones is not present. STD low indicates that CAS has been detected. When STD returns high it indicates that CAS has ended. The timing algorithm consists of 2 components: a tone present guard time (tGP) and a tone absent guard time (tGA). tGP sets the minimum accept duration for CAS. That is, both tones must be detected continuously for tGP for STD to go low to indicate that CAS has been detected. For STD to return high to indicate that CAS has ended, one or both tones must have disappeared for tGA. The purpose of tGA is to bridge over momentary EST dropouts once EST has met the minimum tone duration so as to decrease the likelihood of a long talkoff being broken up into several talkoffs. Usually tGA is set very short or removed altogether because there is another way to deal with the problem (by ignoring further detections for 2 seconds after every detection).
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MT88E45
MT88E45
Advance Information
Vdd
Both Tones Present P Q1 + Comparator R1 N Q2 = Vss EST Rp=R1 || R2 DR/STD Indicates STD in CAS detection mode CAS tDP EST tGP ST/GT tREC tGA tDA tABS tGP=R1C ln [Vdd / (Vdd-VTGt)] tGA=RpC ln Rp=R1 || R2 tGA=0 if R2=0 STD Vdd - Vdiode (Rp/R2) VTGt - Vdiode (Rp/R2) R2 VTGt C ST/GT Vdiode
Figure 5 - CAS Guard Time Circuit Operation Tone present guard time (tGP) operation: In Figure 5 initially there is no CAS, EST is low so Q1 is off. C has been fully charged applying 0V to ST/GT so Q2 is on. When both tones are detected EST goes high and turns off Q2. Because C has been fully charged (ST/GT=0V), the comparator output is low and Q1 stays off. With both Q1 and Q2 off the high at EST discharges C through R1 and the ST/GT voltage increases from 0V. When the voltage exceeds the comparator threshold VTGt, which is typically 0.5 Vdd, the comparator output goes high; Q1 turns on and accelerates the discharge of C (ST/GT goes quickly to Vdd); STD goes low to indicate that a valid CAS has been received. If one or both tones disappeared before tGP has been reached (i.e. when ST/GT voltage is still below VTGt), Q2 turns back on and charges C quickly to bring the ST/GT voltage back to 0V. Then if EST goes high again the tGP duration must start over. Tone absent guard time (tGA) operation: In Figure 5 initially both tones have been detected for tGP so C is fully discharged and ST/GT is at Vdd. While both tones continue to be detected EST stays high; ST/
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GT is at Vdd (the comparator output is high); so Q1 is on and Q2 is off. When one or both tones stop EST goes low and turns off Q1. Because C is fully discharged (ST/GT=Vdd), the comparator output is high and Q2 stays off. With both Q1 and Q2 off the low at EST charges C through Rp=(R1 || R2) and the ST/GT voltage falls towards 0V. When the voltage has fallen below VTGt, the comparator output goes low. Since EST is also low Q2 turns on and accelerates the charging of C so that ST/GT goes quickly to 0V. STD goes high to indicate that the CAS has ended. If EST goes back to high before tGA has been reached (i.e. when ST/GT voltage is still above VTGt), Q1 turns back on and discharges C quickly to bring the ST/GT voltage back to Vdd. Then if EST goes low again the tGA duration must start over. To set tGA=0, set R2 to 0. In Figure 5, tDP is the delay from the start of CAS to EST responding, tDA is the delay from the end of CAS to EST responding. The total delay from the start of CAS to STD responding is tREC=tDP+tGP. The total delay from the end of CAS to STD responding is tABS=tDA+tGA.
Advance Information
MT88E45
North America: Bellcorea 1200 Hz +/- 1% 2200 Hz +/- 1% -4.23 to -36.20 dBm (476 to 12 mVrms)d -48.24 dBm (3mVrms) for On-hook No Ring Signalling such as VMWI 1200 baud +/- 1% -6 to +10 dB Single Tone (f): -18 dB (f<=60Hz) -12 dB (60=3200Hz) 0 dB -3.5 dB Europe: ETSIb UK: BTc
Parameter Mark (Logical 1) Frequency Space (Logical 0) Frequency Received Signal Level Signal Reject Level
1300 Hz +/- 1.5% 2100 Hz +/- 1.5% -5.78 to -33.78 dBme (-8 to -36 dBV)f,g On-hook: -47.78 dBm (-50dBV) 1200 baud +/- 1% -6 to +6 dB >= 25 dB (300 to 3400 Hz) >= 20 dB (300 to 3400 Hz) -5.78 to -37.78 dBm (-8 to -40 dBV)
Transmission Rate Twist (VMARK/VSPACE) Signal to Noise Ratio
Tip/Ring Op-Amp (GS1) Gain Vdd = 5V +/- 10% Tip/Ring Op-Amp (GS1) Gain Vdd = 3V +/- 10%
a. b. c. d. e. f. g. h. i.
-2 dBh -5.5 dBi
0 dB TBD
ANSI/TIA/EIA-716 and draft TIA/EIA-777. Bellcore has agreed to the values and will synchronize its requirements. ETS 300 778-1 (On-hook) Sep 97, ETS 300 778-2 (Off-hook) Jan 98. SIN 227 Issue 3 Nov 97, SIN242 Issue 2 Nov 96. North American on-hook signalling range. The off-hook range is inside the on-hook range: 190mVrms to 12mVrms. dBm - Decibels above or below a reference power of 1 mW into 600 ohms. 0 dBm = 0.7746 Vrms dBV - Decibels above or below a reference voltage of 1 Vrms. 0 dBV = 1 Vrms. ETSI on-hook signalling range. The off-Hook signalling levels are inside this range: -8.78 to -30.78 dBm (-11 to -33 dBV). The 5V ETSI Tip/Ring op-amp gain can be 0 dB if there is no FSK reject level requirement. The 3V ETSI Tip/Ring op-amp gain can be -3.5dB if there is no FSK reject level requirement.
Table 4 - FSK Signal Characteristics
FSK Demodulation
The FSK characteristics are shown in Table 4. In North America, TIA (Telecommunications Industry Association) also defines standards. The Type 1 Caller ID CPE standard is ANSI/TIA/EIA-716. The Type 2 standard is being drafted to become TIA/EIA777. The North American FSK characteristics in Table 4 are from ANSI/TIA/EIA-716. They differ from those Bellcore published in SR-TSV-002476 and SR3004. Bellcore is represented in TR41.3.1 and will synchronize to the TIA requirements in its future documents. The TIA Type 1 standard includes an FSK reject level: * if data is not preceded by ringing (e.g. VMWI), FSK signals below 3mVrms (-48.24 dBm) shall be rejected
*
if data is preceded by ringing, FSK detection may be extended below 3mVrms
The MT88E45 is compliant with the Bellcore/TIA, ETSI and BT requirements with the Tip/Ring op-amp gains in Table 4. In Europe if the country specific FSK requirements do not incorporate ETSI's FSK reject level then the Tip/Ring op-amp gain can also be 0dB at 5V and -3.5dB at 3V to meet the ETSI minimum CAS level for on-hook signalling (-40 dBV). For 3V operation, the FSK receiver becomes more sensitive and lower level signals will be accepted than at 5V. To maintain the FSK reject level, the Tip/ Ring input op-amp gain should be reduced. Note that since the Tip/Ring op-amp is also used for Tip/Ring CAS detection, the CAS level will also be reduced for on-hook detection.
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MT88E45
FSK Data Interface
The MT88E45 provides a powerful dual mode 3-wire interface so that the data bytes in the demodulated FSK bit stream can be extracted without the need either for an external UART or for the CPE's microcontroller to perform the function in software. The interface is specifically designed for the 1200 baud rate and is consisted of 3 pins: DATA, DCLK (Data Clock) and DR (Data Ready). DR/STD is a dual purpose output pin. When FSK is selected it is DR. Two modes (modes 0 and 1) are selectable via the CB0 pin. In mode 0, the FSK bit stream is output directly. In mode 1, the data byte and the trailing stop bit are stored in a 9 bit buffer. If mode 1 is desired, the CB0 pin can be hardwired to Vdd. If mode 0 is desired and full chip power down is not required, the CB0 pin can be hardwired to Vss. In Bellcore's off-hook protocol, a Type 2 CPE should restore the voicepath within 50ms after the end of the FSK signal. Due to noise, end of carrier detection is not always reliable. The draft TIA Type 2 standard has proposed that the CPE must detect the end of FSK when any one of the following occurs: * * absence of carrier signal or, more than five framing errors (trailing stop bit a 0 instead of a 1) have been detected in the FSK message or, more than 150ms of continuous mark signal or space signal has been detected.
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bit, it can also be used to read the stop bit to check for framing error. Alternatively, DCLK and DATA may occupy 2 bits of a microcontroller's input port. The microcontroller polls the input port and saves the DATA bit whenever DCLK changes from low to high. When DR goes low, the word may then be assembled from the last 8 saved bits. DATA may also be connected to a personal computer's serial communication port after conversion from CMOS to RS-232 voltage levels. Mode 1 - Buffer Mode This mode is selected when the CB0 pin is high. In this mode the received byte is stored on chip. At the end of a byte DR goes low to indicate that a new byte has become available. The microcontroller applies DCLK pulses to read the register contents serially out of the DATA pin (see Figure 14). Internal to the MT88E45, the start bit is stripped off, the data bits and the trailing stop bit are sampled and stored. Midway through the stop bit, the 8 data bits and the stop bit are parallel loaded into a 9 bit shift register and DR goes low. The register's contents are shifted out to the DATA pin on the supplied DCLK's rising edges in the order they were received. The last bit must be shifted out and DCLK returned to low before the next DR. DCLK must be low for tDDS before DR goes low and must remain low for tDDH after DR has gone low (see Figure 14). If DCLK begins while DR is low, DR will return to high upon the first DCLK rising edge. If DR interrupts a microcontroller then this feature allows the interrupt to be cleared by the first read pulse. Otherwise DR is low for half a nominal bit time (1/2400 sec). Reading the stop bit allows the software to check for framing errors. When framing error is not checked the microcontroller only needs to send 8 DCLK pulses to shift the data byte out.
*
Mode 0 - Bit Stream Mode This mode is selected when the CB0 pin is low. In this mode the FSK data is output directly to the DATA pin. DCLK and DR pins are timing signal outputs (see Figure 13). For each received stop and start bit sequence, the MT88E45 outputs a fixed frequency clock string of 8 pulses at the DCLK pin. Each DCLK rising edge occurs in the middle of a DATA bit cell. DCLK is not generated for the start and stop bits. Consequently, DCLK will clock only valid data into a peripheral device such as a serial to parallel shift register or a microcontroller. The MT88E45 also outputs an end of word pulse (Data Ready) at the DR pin. DR goes low for half a nominal bit time at the beginning of the trailing stop bit. It can be used to interrupt a microcontroller or cause a serial to parallel converter to parallel load its data into the microcontroller. Since the DR rising edge occurs in the middle of the stop
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Carrier Detect
The carrier detector provides an indication of the presence of a signal in the FSK frequency band. It detects the presence of a signal of sufficient amplitude at the output of the FSK bandpass filter. The signal is qualified by a digital algorithm before the CD output is set low to indicate carrier detection. A 10ms hysteresis is provided to allow for momentary signal dropout once CD has been
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activated. CD is released when there is no activity at the FSK bandpass filter output for 10ms. When CD is inactive (high), the raw output of the FSK demodulator is ignored by the internal data timing recovery circuit. In mode 0 the DATA, DCLK and DR pins are forced high. In mode 1 the output shift register is not updated and DR is high; if DCLK is clocked, DATA is undefined. Note that signals such as speech, CAS and DTMF tones also lie in the FSK frequency band and the carrier detector may be activated by these signals. They will be demodulated and presented as data. To avoid the false data, the MT88E45 should be put into CAS or power down mode when FSK is not expected. Ringing, on the other hand, does not pose a problem as it is ignored by the carrier detector.
MT88E45
In power down mode both input op-amps, VREF and the oscillator are non functional. DCLK becomes an input because to select the power down state CB0 is 1 which will select FSK interface mode 1. If the application uses FSK interface mode 0 and the MT88E45 needs to be powered down then a pull down resistor should be added at the DCLK pin to define its state during power down (R15 in Figure 7). When the MT88E45 is powered down DATA, DR/ STD, CD are high; EST and ST/GT are low. To reduce the operating current an Intelligent Power Down feature has been incorporated. When FSK is selected, the CAS detector is powered down. When CAS is selected the FSK demodulator is powered down. The two input op-amps are not affected and both will remain operational.
Oscillator Interrupt
The DR/STD output can be used to interrupt a microcontroller. When the MT88E45 is the only interrupt source, DR/STD can be connected directly to the microcontroller's interrupt input. Figure 9 shows the necessary connections when the MT88E45 is one of many interrupt sources. The diodes and resistors implement a wired-or so that the microcontroller is interrupted (INT low active or falling edge triggered) when one or more of INT1, INT2 or DR/STD is low. The microcontroller can determine which one of DR/STD, INT1 or INT2 caused the interrupt by reading them into an input port. When system power is first applied and CB0/1/2 have already been configured to select CAS detection, DR/STD will power up as logic low. This is because there is no charge across the ST/GT capacitor in Figure 5, hence ST/GT is at Vdd which causes STD to be low. If DR/STD is used to interrupt a microcontroller the interrupt will not clear until the capacitor has charged up. Therefore upon initial power up the microcontroller should ignore this interrupt source until there is sufficient time to charge the capacitor. Alternatively, the MT88E45 can be put into power down mode: DR/STD goes high and clears the interrupt, ST/GT goes low and the capacitor will charge up quickly. The MT88E45 requires a 3.579545MHz crystal or ceramic resonator to generate its oscillator clock. To meet the CAS detection frequency tolerance specifications the crystal or resonator must have a 0.1% frequency tolerance. The crystal specification is as follows: (e.g. CTS MP036S) Frequency: Frequency Tolerance: Resonance Mode: Load Capacitance: Maximum Series Resistance: Maximum Drive Level: 3.579545MHz 0.1% (over temperature range of the application) Parallel 18pF 150 2mW
Alternatively an external clock source can be used. In which case the OSC1 pin should be driven directly from a CMOS buffer and the OSC2 pin left open. For 5V+/-10% applications any number of MT88E45's can be connected as shown in Figure 6 so that only one crystal is required.
MT88E45 OSC1 OSC2
MT88E45 OSC1 OSC2
MT88E45 OSC1 OSC2
Power Down
3.579545 MHz
to the next MT88E45 (For 5V+/-10% applications only)
The MT88E45 can be powered down to consume virtually no power supply current via a state of the CB0/1/2 pins. Momentary transition of CB0/1/2 into the power down code will not activate power down.
Figure 6 - Common Crystal Connection
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MT88E45
Application Circuits
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Tx+ TIP TIP Telephone Hybrid or Speech IC (Symbolic) Tx-
Microphone
RING
RING
Rx+ Speaker Rx-
R5 C1 R1 D1 R3
R6 MT88E45 VREF IN2+ IN2GS2 CB2 CB1 Vdd CD
R11
R10 R8 C3
D2 D3 C2 R2 D4 = To Microcontroller R4
IN1+ IN1R7 GS1 Vss OSC1 Vss Xtal
R12
R9 C4
Vdd
= From Microcontroller
OSC2 CB0 DCLK
(FSK Interface Mode 1 selected)
C5 ST/GT R13 EST R14 DATA DR/STD D5
C6
R15 is required only if both FSK interface mode 0 and power down features are used.
R15
C6 should be connected directly across Vdd and Vss pins
Unless stated otherwise, resistors are 1%, 0.1Watt; capacitors are 5%, 6.3V. For 1000Vrms, 60Hz isolation from Tip to Earth and Ring to Earth: R1,R2 430K, 0.5W, 5%, 475V min. C1,C2 2n2, 1332V min. (e.g. IRC type GS-3) If the 1000Vrms is handled by other methods then this circuit has to meet the FCC Part 68 Type B Ringer requirements: R1,R2 432K, 0.1W, 1%, 56V min. C1,C2 2n2, 212V min. Common to both sets of R1,R2: R3,R4 34K R8,R9 464K R13 825K R14 226K or 26K1 R15 100K, 20% 5V, 0dB gain 53K6 60K4 464K 3V, -3.5dB gain 35K7 40K2 309K
C3,C4 C5 C6 D1-D4 D5 Xtal
2n2 100n 100n, 20% Diodes. 1N4148 or equivalent Diode. 1N4148 or equivalent 3.579545MHz, 0.1% crystal or ceramic resonator
R5,R10 R6,R11 R7,R12
Figure 7 - Application Circuit: Bellcore MEI Compatible Type 2 Telephone
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MT88E45
1.00 0.95 0.90 0.85 0.80 Gain Ratio 0.75 0.70 0.668 0.65 0.60 0.55 0.531 0.50 3.0 3.5 4.0 Nominal Vdd (Volts) 4.5 5.0
Gain ratio for Bellcore GS1, GS2 ETSI GS2 op amps
0.794
Gain ratio for ETSI GS1 op amp
Figure 8 - Gain Ratio as a Function of Nominal Vdd Gain Setting Resistor Calculation Example for Figure 8: * * For the desired nominal Vdd, use Figure 8 to determine approximate Av. For the GS1 op-amp, start with the 0dB gain setting resistor values of R50dB, R6 0dB and R70dB. In Figure 7 these values are 53K7, 60K4 and 464K respectively. Keep C1,C2,R1,R2,R3,R4 as in Figure 7 to maintain the highpass corner frequency constant for all gain settings. For the desired gain setting of Av: R7Av= R70dB x AV Scaled for desired gain. Choose the closest standard resistor value as R7Av. Actual Av from now on is R7Av/R70db Scaled for good common mode range. Choose the closest standard resistor value as R5Av.
*
R5Av= R50dB x AV
*
Calculate R6Av so that R5Av=R6Av || R7Av. Choose the closest standard resistor value as R6Av. Repeat for R10, R11, R12 for the GS2 op-amp.
1/R6Av = 1/R5Av - 1/R7Av
Example: * For a gain of -3.5dB, Av=10 -3.5/20 = 0.668 * R7 -3.5dB= 464K x 0.668 = 309K9, the closest standard resistor value is 309K. Av is now 309K/464K = 0.666 * R5-3.5dB= 53K6 x 0.666 = 35K7, the closest standard resistor value is 35K7. Therefore R6-3.5dB is calculated to be 40K4, the closest standard resistor value is 40K2.
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MT88E45
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Vdd Interrupt Source 1 INT1 (Open Drain)
Vdd Microcontroller
Resistor (R1) D1 R1 can be opened and D1 shorted if the microcontroller does not read the INT1 pin.
Resistor (R2)
Interrupt Source 2 INT2 (CMOS)
INT(input) MT88E45 DR/STD (CMOS)
Input Port Bit
Figure 9 - Application Circuit: Multiple Interrupt Source
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Absolute Maximum Ratings* - Voltages are with respect to VSS unless otherwise stated
Parameter 1 2 3 4 Supply voltage with respect to Vss Voltage on any pin other than supplies ** Current at any pin other than supplies Storage Temperature Symbol VDD VPIN IPIN TST
SS
MT88E45
Min -0.3 Vss-0.3 -65
DD
Max 6 VDD+0.3 10 150
Units V V mA
oC
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied. ** Under normal operating conditions voltage on any pin except supplies can be minimum V -1V to maximum V +1V for an input current limited to less than 200
Recommended Operating Conditions - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics 1 2 3 4 Power Supplies Clock Frequency Tolerance on Clock Frequency Operating Temperature
oC
Sym VDD fOSC fc TOP
Min 2.7
Typ
Max 5.5
Units V MHz
3.579545 -0.1 -40 +0.1 85
%
oC
Typical figures are at 25
and are for design aid only: not guaranteed and not subject to production testing.
DC Electrical Characteristics
Characteristics 1 Standby Supply Current Sym IDDQ Min Typ 0.1 Max 15 Units A Test Conditions All inputs are VDD/VSS except for oscillator pins. No analog input. outputs unloaded. CB0/1/2 = 1/0/0 All inputs are VDD/VSS except for oscillator pins. No analog input. outputs unloaded.
2
S U P P L Y
Operating Supply Current VDD = 5V 10% VDD = 3V 10% Power Consumption Schmitt Input High Threshold
IDD 3.0 1.7 PO VT+ VTVHYS VIH VIL IOH 0.48*VDD 0.28*VDD 0.2 0.7*VDD VSS 0.8 VDD 0.3*VDD 8 4.5 44 0.68*VDD 0.48*VDD mA mA mW V V V V V mA
3 4
DCLK
Schmitt Input Low Threshold Schmitt Hysteresis
5 6
CB0 CB1 CB2
CMOS Input High Voltage CMOS Input Low Voltage Output High Source Current
7
DCLK DATA DR/STD CD, EST ST/GT
VOH=0.9*VDD
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MT88E45
DC Electrical Characteristics (continued)
Characteristics 8
DCLK DATA DR/STD CD, EST ST/GT IN1+ IN1IN2+ IN2DCLK CB0 CB1 CB2
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Sym IOL
Min 2
Typ
Max
Units mA
Test Conditions VOL=0.1*VDD
Output Low Sink Current
9
Input Current
Iin1
1
A
Vin=VDD to VSS
Iin2
10
A
Vin=VDD to VSS
10 11 12 13
GT
Output HighImpedance Current Output Voltage Output Resistance
Ioz1 VREF RREF VTGt 0.5VDD-0.05 0.5VDD -0.1
5 0.5VDD+0.1 2 0.5VDD+0.05
A V k V
Vout =VDD to VSS No Load
VREF
GT
Comparator Threshold Voltage
DC Electrical Characteristics are over recommended operating conditions, unless otherwise stated. Typical figures are at 25oC and are for design aid only: not guaranteed and not subject to production testing.
AC Electrical Characteristics - CAS Detection
Characteristic 1 2 3 Lower Tone Frequency Upper Tone Frequency Frequency Deviation: Accept Sym fL fH 1.1% Min Typ 2130 2750 Max Unit Hz Hz range within which tones are accepted range outside of which tones are rejected -2 0.22 -46 -43.78 -47.22 -45 -7 SNRCAS 20 +7 dBV dBm dBV dBm dBV dBm dB dB 3,4 1, 5, 6 2, 5, 6 1, 5, 6 Notes*
4
Frequency Deviation: Reject
3.5% -40 -37.78
5 6 7 8 9
Accept Signal Level (per tone) Reject Signal Level (per tone) Vdd=5V +/-10% Reject Signal Level (per tone) Vdd=3V+/-10%, 5V+/-10% Twist: 20 log (V2130Hz/V2750Hz) Signal to Noise Ratio
AC Electrical Characteristics are over recommended operating conditions, unless otherwise stated. Typical figures are at 25oC and are for design aid only: not guaranteed and not subject to production testing *Notes: 1. Tip/Ring signal level. Input op-amp configured to 0dB gain at Vdd=5V+/-10%, -3.5dB at Vdd=3V+/-10%. 2. Tip/Ring signal level. Input op-amp configured to 0dB gain at Vdd=5V+/-10%. 3. Both tones have the same amplitude. 4. Band limited random noise 300-3400Hz. Measurement valid only when tone is present. 5. dBV - Decibels above or below a reference voltage of 1 Vrms. 0 dBV = 1 Vrms. Signal level is per tone. 6. dBm - Decibels above or below a reference power of 1 mW into 600 ohms. 0 dBm = 0.7746 Vrms. Signal level is per tone.
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AC Electrical Characteristics - FSK Demodulation
Characteristics 1 Accept Signal Level Range Sym Min -40 -37.78 10.0 Typ Max -6.45 -4.23 476 -48.24 -50.46 3 1188 1188 2178 1280.5 2068.5 -6 SNRFSK 20 1200 1200 2200 1300 2100 1212 1212 2222 1319.5 2131.5 +10 Units
MT88E45
Notes* 1, 2, 4, 5
dBV dBm mVrms dBm dBV mVrms baud Hz Hz Hz Hz dB dB
2 3 4
Bell 202 Format Reject Signal Level Transmission Rate Mark and Space Frequencies Bell 202 1 (Mark) Bell 202 0 (Space) CCITT V.23 1 (Mark) CCITT V.23 0 (Space)
1, 2, 4, 5
5 6
Twist: 20 log (VMARK/VSPACE) Signal to Noise Ratio
1,3
AC Electrical Characteristics are over recommended operating conditions, unless otherwise stated. Typical figures are nominal values and are for design aid only: not guaranteed and not subject to production testing. *Notes: 1. Both mark and space have the same amplitude. 2. Tip/Ring signal level. Input op-amp configured to 0dB gain at Vdd=5V+/-10%, -3.5dB at Vdd=3V+/-10%. 3. Band limited random noise (200-3400Hz). Present when FSK signal is present. Note that the BT band is 300-3400Hz, the Bellcore band is 0-4kHz. 4. dBV - Decibels above or below a reference voltage of 1 Vrms. 0 dBV = 1 Vrms. 5. dBm - Decibels above or below a reference power of 1 mW into 600 ohms. 0 dBm = 0.7746 Vrms.
Electrical Characteristics - Gain Setting Amplifiers
Characteristics 1 2 3 4 5 6 7 8 9 10 11 Input Leakage Current Input Resistance Input Offset Voltage Power Supply Rejection Ratio Common Mode Rejection DC Open Loop Voltage Gain Unity Gain Bandwidth Output Voltage Swing Capacitive Load (GS1,GS2) Resistive Load (GS1,GS2) Common Mode Range Voltage Sym IIN Rin VOS PSRR CMRR AVOL fC VO CL RL VCM 100 1.0
VDD-1.0
Min
Max 1
Units A M
Test Conditions VSS VIN VDD
10 25 30 40 40 0.3 0.5
VDD-0.7
mV dB dB dB MHz V pF k V Load 100k 1kHz ripple on VDD VCMmin VIN VCMmax
50
Electrical characteristics are over recommended operating conditions, unless otherwise stated.
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MT88E45
AC Electrical Characteristics - CAS Detection Timing
Characteristics 1 Tone present detect time Sym tDP Min 0.5 Max 10 Units ms
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Notes See Figures 16, 17 See Figures 16, 17
2 Tone absent detect time tDA 0.1 8 ms AC Electrical Characteristics are over recommended operating conditions unless otherwise stated.
AC Electrical Characteristics - 3-Wire Interface Timing
Characteristics 1
OSC2
Sym tPU tPD tCP tCA
Min
Max 50 10 25
Units ms ms ms ms ms
Notes
Power-up time Power-down time Input FSK to CD low delay
CD
2 3 4 5
Input FSK to CD high delay Hysteresis
10 10
AC Electrical Characteristics are over recommended operating conditions unless otherwise stated.
AC Electrical Characteristics - 3-Wire Interface Timing (Mode 0)
Characteristics 1 2 3 4 5 6 7 8 9 10 11 12 13
DCLK DR/STD DCLK DATA DCLK DATA DR/STD
Sym tRR tRF tRL
Min
Typ
Max 200 200
Units ns ns s baud ms ns ns s s
Notes* into 50pF Load into 50pF Load 2 1
Rise time Fall time Low time Rate Input FSK to DATA delay Rise time Fall time DATA to DCLK delay DCLK to DATA delay Frequency High time Low time DCLK to DR delay
415 1188
416 1200 1
417 1212 5 200 200
tIDD tR tF tDCD tCDD fDCLK0 tCH tCL tCRD 6 6 1201.6 415 415 415
into 50pF Load into 50pF Load 1, 2, 3 1, 2, 3 2 2 2 2
416 416 1202.8 416 416 416 1204 417 417 417
Hz s s s
AC Electrical Characteristics are over recommended operating conditions unless otherwise stated. Typical figures are at 25oC and are for design aid only: not guaranteed and not subject to production testing. *Notes: 1. FSK input data at 1200 12 baud. 2. OSC1 at 3.579545 MHz 0.1%. 3. Function of signal condition.
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AC Electrical Characteristics - 3-Wire Interface Timing (Mode 1)
Characteristics 1 2 3 4 5
DCLK DR/STD DCLK
MT88E45
Sym fDCLK1
Min
Max 1
Units MHz % ns ns ns
Notes
Frequency Duty cycle Rise time DCLK low set up to DR DCLK low hold time after DR
30 tR1 tDDS tDDH 500 500
70 100
AC Electrical Characteristics are over recommended operating conditions unless otherwise stated.
AC Electrical Characteristics - Timing Parameter Measurement Voltage Levels
Characteristics 1 2 3 CMOS Threshold Voltage Rise/Fall Threshold Voltage High Rise/Fall Threshold Voltage Low Sym VCT VHM VLM Level 0.5*VDD 0.7*VDD 0.3*VDD Units V V V Notes
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MT88E45
tDCD tCDD
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DATA tR DCLK tCL tR tCH tF tF
VHM VCT VLM VHM VCT VLM
Figure 10 - DATA and DCLK Mode 0 Output Timing
tRF
tRR
DR tRL
VHM VCT VLM
Figure 11 - DR Output Timing
VHM
DCLK
VLM
tR1
Figure 12 - DCLK Mode 1 Input Timing
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MT88E45
start start b0 b1 b2 b3 b4 b5 b6 b7 stop stop start b0 b1 b2 b3 b4 b5 b6 b7 stop stop start b0 b1 b2 b3 b0 b1 b2 b3 b4 b5
start TIP/RING (A/B) WIRES b7 stop b0 b1 b2 b3 b4 b5 b6 b7
DATA (Output)
b6 b7
tIDD start b0 b1 b2 b3 b4 b5 b6 b7 stop
DCLK (Output) tCH DR (Output) tRL tCL tCRD 1/fDCLK0
Figure 13 - Serial Data Interface Timing (Mode 0)
Demodulated Data (Internal Signal) DR (Data Ready) (Output)
Word N 7 stop start Note 1 >tDDS >tDDH 1/fDCLK1 0 1 2
Word N+1 3 4 5 6 7 stop tRL Note 2
DCLK (Data Clock) (Schmitt Input) DATA (Output) 7 stop 0 1 2 3 4 5 6 7 stop 0
Word N-1
Word N
The DCLK input must be low before and after DR falling edge. Note 1: DCLK occurs during DR low and returns DR to high. Note 2: DCLK occurs after DR, so DR is low for half a nominal bit time.
Figure 14 - Serial Data Interface Timing (Mode 1)
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MT88E45
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TIP/RING
1st Ring A B
Ch. seizure C
Mark D
Data E F
2nd Ring
PWDN
Note 1
Note 2
Note 3
Note 2
Note 4
tPU OSC2 FSKen tCP CD DR
Note 5
tPD
Note 1
tCA
DCLK
DATA
..101010..
Data
A = 2sec typical B = 250-500ms C = 250ms D = 150ms E = feature specific Max C+D+E = 2.9 to 3.7sec F 200ms
Figure 15 - Application Timing for Bellcore On-hook Data Transmission Associated with Ringing, e.g., CID
Notes: This on-hook case application is included because a CIDCW (off-hook) CPE should also be capable of receiving on-hook data transmission (with ringing) from the end office. 1) PWDN and FSKen are internal signals decoded from CB0/1/2. 2) The CPE designer may choose to enable the MT88E45 only after the end of ringing to conserve power in a battery operated CPE. CD is not activated by ringing. 3) The microcontroller in the CPE powers down the MT88E45 after CD has become inactive. 4) The microcontroller times out if CD is not activated. 5) This signal represents the mode of the DR/STD pin.
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MT88E45
CPE unmutes handset and enables keypad Data F G
CPE goes off-hook TIP/RING
Note 1
CPE mutes handset & disables keypad CPE sends
Note 5
CAS A B
ACK C
Mark E
D
PWDN
Note 8
Hybrid CASen
Note 8
FSKen
Note 8
Note 2
Note 3
Note 4
tPU OSC2 tDP tDA tGA VTGt tABS
EST
ST/GT
tGP tREC
STD
Note 9 Note 6 Note 7
tCP
tCA
CD
DR
Note 9
DCLK
DATA
Data
A = 75-85ms B = 0-100ms C = 55-65ms D = 0-500ms E = 58-75ms F = feature specific G 50ms
Figure 16 - Application Timing for Bellcore Off-hook Data Transmission, e.g., CIDCW
Notes: 1) In a CPE where AC power is not available, the designer may choose to switch over to line power when the CPE goes off-hook and use battery power while on-hook. The CPE must also be CID (on-hook) capable because a CIDCW CPE includes CID functionality. 2) Non-FSK signals such as CAS, speech and DTMF tones are in the same frequency band as FSK. They will be demodulated and give false data. Therefore the MT88E45 should be taken out of FSK mode when FSK is not expected. 3) The MT88E45 may be put into FSK mode as soon as the CPE has finished sending the acknowledgment signal ACK. TR-NWT000575 specifies that ACK = DTMF `D' for non-ADSI CPE, `A' for ADSI CPE. 4) The MT88E45 should be taken out of FSK mode when CD has become inactive, or after 5 framing errors have been detected, or after 150ms of continuous mark signal or space signal has been received. The framing errors need not be consecutive. 5) In an unsuccessful attempt where the end office does not send the FSK signal, the CPE should unmute the handset and enable the keypad after interval D has expired. 6) The total recognition time is tREC = tGP + t DP , where tGP is the tone present guard time and tDP is the tone present detect time. V TGt is the comparator threshold (refer to Figure 5 for details). 7) The total tone absent time is tABS = tGA + tDA , where t GA is the tone absent guard time and tDA is the tone absent detect time. V TGt is the comparator threshold (refer to Figure 5 for details). 8) PWDN, Hybrid CASen and FSKen are internal signals decoded from CB0/1/2. 9) This signal represents the mode of the DR/STD pin.
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MT88E45
Line Reversal `Idle State Tone Alert Signal' Ch. seizure DT-AS A B C D Mark E Data F G
Advance Information
A/B Wires PWDN
Note 6
Ring
Note 4 50-150ms
Tip/Ring CASen
Note 6
tDP tGP
tDA tGA VTGt
EST
Note 1 Note 2
ST/GT
tREC
STD
Note 7 151ms
tABS
Note 3
TE DC load
< 0.5mA (optional) <120A 205ms Current wetting pulse (see SIN227) Zss (Refer to SIN227) Note 4
TE AC load
FSKen
Note 6
Note 5
tCP
CD DR
Note 7
tCA A 100ms B = 88-110ms C 45ms (up to 5sec) D = 80-262ms E = 45-75ms F 2.5sec (typ. 500ms) G > 200ms Note: All values obtained from SIN227 Issue 1
DCLK
DATA
..101010..
Data
tPU
OSC2
tPD
Figure 17 - Application Timing for BT Caller Display Service (CDS), e.g., CLIP
Notes: 1) The total recognition time is tREC = tGP + t DP , where t GP is the tone present guard time and t DP is the tone present detect time. VTGt is the comparator threshold (refer to Figure 5 for details). 2) The total tone absent time is tABS = t GA + tDA , where tGA is the tone absent guard time and tDA is the tone absent detect time. VTGt is the comparator threshold (refer to Figure 5 for details). 3) By choosing t GA=15ms, tABS will be 15-25ms so that the current wetting pulse and AC load can be applied right after the STD rising edge. 4) SIN227 specifies that the AC and DC loads should be removed between 50-150ms after the end of the FSK signal, indicated by CD returning to high. The MT88E45 may also be powered down at this time. 5) The MT88E45 should be taken out of FSK mode when FSK is not expected to prevent the FSK demodulator from reacting to other in-band signals such as speech, DT-AS/CAS and DTMF tones. 6) PWDN, Tip/Ring CASen, FSKen are internal signals decoded from CB0/1/2. 7) This signal represents the mode of the DR/STD pin.
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Advance Information
MT88E45
Line Reversal (Optionally sent)
First Complete Ring Cycle Ch. seizure Mark D Data E
Note 2 50-150ms
A/B Wires
Ring Burst A
Note 1 250-400ms
B
C
F
PWDN
Note 3
TE DC load
TE AC load FSKen
Note 3
tCP CD
tCA
Note 4
DR
DCLK
DATA tPU OSC2
..101010..
Data tPD
A = 200-450ms B 500ms C = 80-262ms D = 45-262ms E 2.5s (typ. 500ms) F >200ms Note: Parameter F from "CCA Exceptions Document Issue 3"
Figure 18 - Application Timing for UK's CCA Caller Display Service (CDS), e.g., CLIP
Notes: 1) From TW/P&E/312. Start time: The CPE should enter the signalling state by applying the DC and AC terminations within this time after the end of the ring burst. 2) End time: The CPE should leave the signalling state by removing the DC and AC terminations within this time after the end of Data, indicated by CD returning to high. The MT88E45 should also be taken out of FSK mode at this time to prevent the FSK demodulator from reacting to other in-band signals such as speech, and DTMF tones. 3) PWDN and FSKen are internal signals decoded from CB0/1/2. 4) This signal represents the mode of the DR/STD pin.
25
Package Outlines
Pin 1
E
A
C L H
e D 4 mils (lead coplanarity) Notes: 1) Not to scale 2) Dimensions in inches 3) (Dimensions in millimeters) 4) A & B Maximum dimensions include allowable mold flash B L
A1
DIM
A A1 B C D E e H L
16-Pin Min
0.093 (2.35) 0.004 (0.10) 0.013 (0.33) 0.009 (0.231) 0.398 (10.1) 0.291 (7.40)
18-Pin Min
0.093 (2.35) 0.004 (0.10) 0.013 (0.33) 0.009 (0.231) 0.447 (11.35) 0.291 (7.40)
20-Pin Min
0.093 (2.35) 0.004 (0.10) 0.013 (0.33) 0.009 (0.231) 0.496 (12.60) 0.291 (7.40)
24-Pin
Min 0.093 (2.35) 0.004 (0.10) 0.013 (0.33) 0.009 (0.231) 0.5985 (15.2) 0.291 (7.40) Max 0.104 (2.65) 0.012 (0.30) 0.020 (0.51) 0.013 (0.318) 0.614 (15.6) 0.299 (7.40) Min
28-Pin
Max 0.104 (2.65) 0.012 (0.30) 0.020 (0.51) 0.013 (0.318) 0.7125 (18.1) 0.299 (7.40)
Max
0.104 (2.65) 0.012 (0.30) 0.020 (0.51) 0.013 (0.318) 0.413 (10.5) 0.299 (7.40)
Max
0.104 (2.65) 0.012 (0.30) 0.030 (0.51) 0.013 (0.318) 0.4625 (11.75) 0.299 (7.40)
Max
0.104 (2.65) 0.012 (0.30) 0.020 (0.51) 0.013 (0.318) 0.512 (13.00) 0.299 (7.40)
0.093 (2.35) 0.004 (0.10) 0.013 (0.33) 0.009 (0.231) 0.697 (17.7) 0.291 (7.40)
0.050 BSC (1.27 BSC) 0.394 (10.00) 0.016 (0.40) 0.419 (10.65) 0.050 (1.27)
0.050 BSC (1.27 BSC) 0.394 (10.00) 0.016 (0.40) 0.419 (10.65) 0.050 (1.27)
0.050 BSC (1.27 BSC) 0.394 (10.00) 0.016 (0.40) 0.419 (10.65) 0.050 (1.27)
0.050 BSC (1.27 BSC) 0.394 (10.00) 0.016 (0.40) 0.419 (10.65) 0.050 (1.27)
0.050 BSC (1.27 BSC) 0.394 (10.00) 0.016 (0.40) 0.419 (10.65) 0.050 (1.27)
Lead SOIC Package - S Suffix
NOTES: 1. Controlling dimensions in parenthesis ( ) are in millimeters. 2. Converted inch dimensions are not necessarily exact.
General-7
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