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19-1703; Rev 1; 8/01
+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers
General Description
The MAX3171/MAX3173 are three-driver/three-receiver multiprotocol transceivers that operate from a single +3.3V supply. The MAX3171/MAX3173, along with the MAX3170 and MAX3172/MAX3174, form a complete software-selectable data terminal equipment (DTE) or data communications equipment (DCE) interface port that supports V.28 (RS-232) and V.10/V.11 (RS-449, V.36, EIA-530, EIA-530-A, X.21, RS-423) protocols. The MAX3171/MAX3173 transceivers carry the serial interface control signaling; the MAX3170 transceivers carry the clock and data signals. The MAX3172/ MAX3174 have an extra transceiver for applications requiring four transceivers for control signaling. An internal charge pump and proprietary low-dropout transmitter output stage allow V.28, V.11, and V.10 compliant operation from a single +3.3V supply. A nocable mode is entered when all mode pins (M0, M1, and M2) are pulled high or left unconnected. In nocable mode, supply current decreases to 2mA and all transmitter and receiver outputs are disabled (high impedance). Short-circuit limiting and thermal-shutdown circuits protect the drivers against excessive power dissipation. The MAX3171 features 10s deglitching on the V.10/V.11/V.28 receiver inputs. The MAX3173 is available for applications that do not require deglitching on the serial handshake signals. These parts require only four surface-mount capacitors for charge-pump operation in addition to supply bypassing.
CTS DSR DCD DTR RTS LL
Features
o Industry's First +3.3V Multiprotocol Transceiver o Certified TBR-1 and TBR-2 Compliant (NET1 and NET2) o Supports V.28 (RS-232) and V.10/V.11 (RS-449, V.36, EIA-530, EIA-530-A, X.21, RS-423) Protocols o 3V/5V Logic Compatibility o o o o o Software-Selectable DCE/DTE True Fail-Safe Receiver Operation Available in Small 28-Pin SSOP Package 10s Receiver Input Deglitching (MAX3171 only) All Transmitter Outputs Fault Protected to 15V, Tolerate Cable Miswiring
MAX3171/MAX3173
________________________Applications
Data Networking CSU and DSU PCI Cards Telecommunications
Ordering Information
PART MAX3171CAI MAX3173CAI TEMP. RANGE 0C to +70C 0C to +70C PIN-PACKAGE 28 SSOP 28 SSOP
Data Routers Pin Configuration appears at end of data sheet
Typical Operating Circuit
RXD RXC TXC SCTE TXD
MAX3171 MAX3173
R3
R2
R1
D3
D2
D1 MAX3172 MAX3174
R3
R2
R1
D3
D2
D1 MAX3170
R4 D4
13 5 CTS B CTS A
10 8 DSR B DSR A
22 6 DCD B DCD A
23 20 19 4 DTR B DTR A RTS B RTS A
1 SHIELD
7 SG DB-25 CONNECTOR
18 LL A
16 3
9 17
12 15 11 24 14 2 TXC B TXC A SCTE B SCTE A TXD B TXD A
________________________________________________________________ Maxim Integrated Products
RXD B RXD A RXC B RXC A
1
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+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers MAX3171/MAX3173
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND unless otherwise noted.) Supply Voltages VCC ......................................................................-0.3V to +4V V+ (Note 1) ..........................................................-0.3V to +7V V- (Note 1) ...........................................................+0.3V to -7V V+ to V- (Note 1) ...............................................................13V Logic Input Voltages M0, M1, M2, DCE/DTE, T_IN ...............................-0.3V to +6V Logic Output Voltages R_OUT ...................................................-0.3V to (VCC + 0.3V) Short-Circuit Duration............................................Continuous Transmitter Outputs T_OUT_...............................................................-15V to +15V Short-Circuit Duration ........................................................60s Receiver Inputs R_IN_ ..................................................................-15V to +15V Continuous Power Dissipation (TA = +70C) 28-Pin SSOP (derate 11.1mW/C above +70C) ........889mW Operating Temperature Range MAX3171CAI/MAX3173CAI ...............................0C to +70C Storage Temperature Range ............................-65C to +150C Lead Temperature (soldering, 10s) ................................+300C
Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC = 3.3V 5%; C1 = C2 = 1F, C3 = C4 = C5 = 3.3F, and TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25C.) (Note 2)
PARAMETER DC CHARACTERISTICS V.11/V.10 modes Supply Current (DCE Mode, Digital Inputs = GND or VCC, Transmitter Outputs Static) V.11/V.10 modes (no load) ICC V.28 mode V.28 mode (no load) No-cable mode V.11/V.10 modes (no load) Internal Power Dissipation PD V.11/V.10 modes (full load) V.28 mode (full load) No-cable mode V.11/V.10 modes (no load) V+ Output Voltage V+ V.11/V.10 modes (full load) V.28 mode No-cable mode V.11/V.10 modes (no load) V- Output Voltage VV.11/V.10 modes (full load) V.28 mode No-cable mode Charge-Pump Enable Time LOGIC INPUTS (M0, M1, M2, DCE/DTE, T_IN) Input High Voltage Input Low Voltage Logic Input Current VIH VIL T_IN IIH, IIL M0, M1, M2, DCE / DTE = VCC M0, M1, M2, DCE / DTE = GND 30 50 2.0 0.8 1 1 100 A V V Delay until V+ and V- specifications met -4.2 1 ms 4.4 4.2 5.55 4.6 -4.0 -3.8 -5.45 V V 220 6 24 6 2 20 450 40 6.6 mW 300 23 40 23 8 mA SYMBOL CONDITIONS MIN TYP MAX UNITS
2
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+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers
ELECTRICAL CHARACTERISTICS (continued)
(VCC = 3.3V 5%; C1 = C2 = 1F, C3 = C4 = C5 = 3.3F, and TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC
PARAMETER LOGIC OUTPUTS (R_OUT) Output High Voltage Output Low Voltage Rise or Fall Time Output Leakage Current (Receiver Output Three-Stated) TRANSMITTER OUTPUTS Output Leakage Current IZ -0.25V VOUT +0.25V, power off or no-cable mode V.28 Data Rate Receiver Glitch Rejection (MAX3171 only) Receiver Input Resistance RIN V.10 V.11 Minimum pulse width passed Minimum pulse width rejected -10V VAB +10V, VA or VB grounded, V.11/V.35, no-cable mode -15V VA +15V, V.28 mode MAX3171 Data Rate MAX3173 V.11 TRANSMITTER Unloaded Differential Output Voltage Loaded Differential Output Voltage Change in Magnitude of Output Differential Voltage Common-Mode Output Voltage Change in Magnitude of Output Common-Mode Voltage Short-Circuit Current Rise or Fall Time Transmitter Input to Output Data Skew Output-to-Output Skew Channel-to-Channel Skew V.11 RECEIVER Differential Threshold Voltage Input Hysteresis VTH VTH -7V VCM +7V -7V VCM +7V -200 5 -100 15 -25 mV mV VODO VODL VOD VOC VOC ISC tr, tf tPHL, tPLH tSKEW R = 1.95k, Figure 1 R = 50, Figure 1 R = 50, Figure 1 R = 50, Figure 1 R = 50, Figure 1 T_OUTA/B = GND 10% to 90%, Figure 2 Figure 2 Figure 2 60 10 50 2 2 2 4.0 0.5 VODO 0.2 3.0 0.2 150 25 80 10 6.0 V V V V V mA ns ns ns ns ns V.10/V.28 V.11 V.10/V.28 V.11 20 3 40 5 64 64 240 10 Mbps kbps 7 5 15 -100 240 115 10 100 A kbps Mbps s VOH VOL tr, tf ISOURCE = 1.0mA ISINK = 1.6mA 10% to 90%, Figure 4 R_OUT = GND R_OUT = VCC 30 15 50 100 1 VCC - 1.0 0.4 V V ns A SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX3171/MAX3173
K
| tPHL - tPLH | Figure 2
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+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers MAX3171/MAX3173
ELECTRICAL CHARACTERISTICS (continued)
(VCC = 3.3V 5%; C1 = C2 = 1F, C3 = C4 = C5 = 3.3F, and TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3.3V, TA = +25C.) (Note 2)
PARAMETER Receiver Input to Output Data Skew V.10 TRANSMITTER Unloaded Output Voltage Loaded Output Voltage Swing Short-Circuit Current Transmitter Rise or Fall Time Transmitter Input to Output Data Skew V.10 RECEIVER Threshold Voltage Input Hysteresis Receiver Input to Output Data Skew V.28 TRANSMITTER Output Voltage Swing Short-Circuit Current VO ISC All transmitters loaded with RL = 3k No load T_OUTA = GND RL = 3k, CL = 2500pF, measured from +3V to -3V or from -3V to +3V, Figure 3 Output Slew Rate SR RL = 7k, CL = 150pF, measured from +3V to -3V or from -3V to +3V, Figure 3 Transmitter Input to Output Data Skew V.28 RECEIVER Input Threshold Low Input Threshold High Input Hysteresis Propagation Delay Data Skew VIL VIH VHYS tPLH, tPHL | tPHL - tPLH | MAX3171, Figure 4 MAX3173, Figure 4 MAX3171, Figure 4 MAX3173, Figure 4 0.5 100 5 2.0 0.5 10 200 4.0 15 0.8 V V V s s ns tPHL, tPLH | tPHL - tPLH | Figure 3 Figure 3 6 1 100 30 s ns 4 25 5.0 5.4 6.5 60 30 V/s V mA VTH VTH tPHL, tPLH | tPHL - tPLH | MAX3171, Figure 4 MAX3173, Figure 4 MAX3171, Figure 4 MAX3173, Figure 4 5 +25 +100 15 10 60 0.5 5 15 120 4 16 +300 mV mV s ns s ns SYMBOL tPHL, tPLH | tPHL - tPLH | MAX3171 MAX3173 MAX3171 MAX3173 RL = 3.9k, Figure 3 RL = 450, Figure 3 T_OUTA = GND RL = 450, CL = 100pF, Figure 3 RL = 450, CL = 100pF, Figure 3 RL = 450, CL =100pF, Figure 3 4.0 0.9 VODO 100 2 2 50 150 CONDITIONS MIN 5 TYP 10 60 0.5 5 4.4 MAX 15 120 4 16 6.0 UNITS s ns s ns V V mA s s ns
VODO VODL ISC tr, tf tPHL, tPLH | tPHL - tPLH |
Note 2: V+ and V- are also used to supply the MAX3172/MAX3174. The MAX3171/MAX3173 are tested with additional current load on V+ and V- to capture the effect of loading from the MAX3172/MAX3174 in all operation modes. 4 _______________________________________________________________________________________
+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers
Typical Operating Characteristics
(VCC = +3.3V, C1 = C2 = 1.0F, C3 = C4 = C5 = 3.3F, TA = +25C, unless otherwise noted.)
V.10/V.11 MODE SUPPLY CURRENT vs. DATA RATE
MAX3171 toc01
MAX3171/MAX3173
V.28 MODE SUPPLY CURRENT vs. DATA RATE
MAX3171 toc02
V.11 LOADED DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE
RL = 100 VOUT+ 3 OUTPUT VOLTAGE (V) 2 1 0 -1 -2 VOUTMAX3171 toc03
250 FULL LOAD 200 SUPPLY CURRENT (mA)
80 70 SUPPLY CURRENT (mA) 60 50 40 30 20 FULL LOAD
4
150
100
50
NO LOAD 10 NO LOAD -3 -4 0.01 0.1 1k 10k 100k 1000k -40
0 0.001
0.01
0.1
1k
10k
100k
1000k
0 0.001
-15
10
35
60
85
DATA RATE (kbps)
DATA RATE (kbps)
TEMPERATURE (C)
V.28 LOADED OUTPUT VOLTAGE vs. TEMPERATURE
RL = 3k 6 VOUT+ OUTPUT VOLTAGE (V) 4 2 0 -2 -4 -6 -8 -40 -15 10 35 60 85 TEMPERATURE (C) VOUTMAX3171 toc04
V.10 LOADED OUTPUT VOLTAGE vs. TEMPERATURE
MAX3171 toc05
V.10/V.11 RECEIVER INPUT CURRENT vs. INPUT VOLTAGE
MAX3171 toc06
8
5 4 3 OUTPUT VOLTAGE (V) 2 1 0 -1 -2 -3 -4 -5 -40 -15 10 35 60 VOUTVOUT+ RL = 450
0.3 0.2 INPUT CURRENT (mA) 0.1 0 -0.1 -0.2 -0.3
85
-10
-5
0 INPUT VOLTAGE (V)
5
10
TEMPERATURE (C)
V.28 RECEIVER INPUT CURRENT vs. INPUT VOLTAGE
MAX3171 toc07
V.28 SLEW RATE vs. LOAD CAPACITANCE
16 14 12 10 8 6 4 2 0 0 0 500 1000 1500 2000 2500 3000 -SLEW +SLEW RISE/FALL TIME (s) SLEW RATE (V/s)
MAX3171toc11
V.10 TRANSMITTER RISE AND FALL TIMES vs. LOAD CAPACITANCE
MAX3171toc12
4 3 INPUT CURRENT (mA) 2 1 0 -1 -2 -3 -4 -15 -10 -5 0 5 10
18
2.5
2.0 FALL 1.5 RISE 1.0
0.5
15
0
500
1000
1500
2000
2500
3000
INPUT VOLTAGE (V)
CAPACITANCE (pF)
CAPACITANCE (pF)
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+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers MAX3171/MAX3173
Typical Operating Characteristics (continued)
(VCC = +3.3V, C1 = C2 = 1.0F, C3 = C4 = C5 = 3.3F, TA = +25C, unless otherwise noted.)
MAX3173 LOOPBACK SCOPE PHOTO V.11 MODE (UNLOADED)
MAX3171 toc08
MAX3171 LOOPBACK SCOPE PHOTO V.28 MODE (RL = 3k)
MAX3171 toc09
MAX3173 LOOPBACK SCOPE PHOTO 530A MODE (UNLOADED)
MAX3171 toc10
ROUT TOUT/ RIN
ROUT TOUT/ RIN
ROUT2 TOUT2/ RIN2
5V/div
5V/div
5V/div
TIN
TIN
TIN2
10s/div
10s/div
10s/div
Test Circuits
100pF
R VOD
Tx 100 Rx 50pF
R
VOC
100pF
Figure 1. V.11 DC Test Circuit
Figure 2. V.11 AC Test Circuit
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+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceiver MAX3171/MAX3173
Test Circuits (continued)
Tx Tx Rx
CL
RL
50pF
Figure 3. V.10/V.28 Driver Test Circuit
Figure 4. V.10/V.28 Receiver Test Circuit
Pin Description
PIN 1 2 3 4 5, 6, 7 8, 9, 10 11, 12, 13 14 15, 18 16, 17 19 20 21, 23 22, 24 25 26 27 28 NAME V+ C2+ C2VT_IN R_OUT M_ DCE/DTE R_INB R_INA T3OUTB/R1INB T3OUTA/R1INA T_OUTB T_OUTA C1GND VCC C1+ FUNCTION Positive Supply Generated by the Charge Pump (connect to V+ pin of MAX3172/MAX3174). Bypass V+ to ground with a 3.3F ceramic capacitor. Positive Terminal of the Inverting Charge-Pump Capacitor. Connect C2+ to C2- with a 1F ceramic capacitor. Negative Terminal of the Inverting Charge-Pump Capacitor. Connect C2+ to C2- with a 1F ceramic capacitor. Negative Supply Generated by the Charge Pump (connect to V- pin of MAX3172/MAX3174). Bypass V- to ground with a 3.3F ceramic capacitor. Transmitter CMOS Inputs (T1IN, T2IN, T3IN) Receiver CMOS Outputs (R1OUT, R2OUT, R3OUT) Mode Select Inputs (M0, M1, M2). Internally pulled up to VCC. See Table 1 for detailed information. DCE/DTE Mode Select Input. Logic level high selects DCE interface; logic level low selects DTE interface. Internally pulled up to VCC. Noninverting Receiver Inputs (R3INB, R2INB) Inverting Receiver Inputs (R3INA, R2INA) Noninverting Transmitter Output/Noninverting Receiver Input Inverting Transmitter Output/Inverting Receiver Input Noninverting Transmitter Outputs (T2OUTB, T1OUTB) Inverting Transmitter Outputs (T2OUTA, T1OUTA) Negative Terminal of the Voltage-Doubler Charge-Pump Capacitor. Connect C1+ to C1- with a 1F ceramic capacitor. Ground +3.3V Supply Voltage (5%). Bypass VCC to ground with a 3.3F ceramic capacitor. Positive Terminal of the Voltage-Doubler Charge-Pump Capacitor. Connect C1+ to C1- with a 1F ceramic capacitor.
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+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers MAX3171/MAX3173
Table 1. Mode Selection
PROTOCOL V.11 RS-530A RS-530 X.21 V.35 RS-449/V.36 V.28/RS-232 No cable V.11 RS-530A RS-530 X.21 V.35 RS-449/V.36 V.28/RS-232 No cable LOGIC INPUTS M2 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 M1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 M0 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 DCE/DTE 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 T1 V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z TRANSMITTERS T2 V.11 V.10 V.11 V.11 V.28 V.11 V.28 Z V.11 V.10 V.11 V.11 V.28 V.11 V.28 Z T3 Z Z Z Z Z Z Z Z V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z R1 V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z Z Z Z Z Z Z Z Z RECEIVERS R2 V.11 V.10 V.11 V.11 V.28 V.11 V.28 Z V.11 V.10 V.11 V.11 V.28 V.11 V.28 Z R3 V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z V.11 V.11 V.11 V.11 V.28 V.11 V.28 Z
Z = High impedance
1 C3 3.3F C2 1F 2 3 4 C4 3.3F
28 V+ MAX3173 C1+ C2+ C2VVCC GND C127 26 25 C5 3.3F C1 1F
MAX3171
The MAX3171/MAX3173 feature a 2mA no-cable mode, true fail-safe operation, and thermal shutdown circuitry. Thermal shutdown protects the drivers against excessive power dissipation. When activated, the thermal shutdown circuitry places the driver outputs into a highimpedance state.
Mode Selection
The state of mode select pins M0, M1, and M2 determines which serial interface protocol is selected (Table 1). The state of the DCE/DTE input determines whether the transceivers will be configured as a DTE serial port or a DCE serial port. When the DCE/DTE input is logic HIGH, driver T3 is activated and receiver R1 is disabled. When the DCE/DTE input is logic LOW, driver T3 is disabled and receiver R1 is activated. M0, M1, M2, and DCE/DTE are internally pulled up to VCC to ensure logic HIGH if left unconnected. The MAX3171/MAX3173's mode can be selected through software control of the M0, M1, M2, and DCE/DTE inputs. Alternatively, the mode can be selected by shorting the appropriate combination of mode control inputs to GND (the inputs left floating will be internally pulled up to VCC). If the M0, M1, and M2 mode inputs are all unconnected, the MAX3171/ MAX3173 will enter no-cable mode.
Figure 5. Charge-Pump Connections
Detailed Description
The MAX3171/MAX3173 are three-driver/three-receiver multiprotocol transceivers that operate from a single +3.3V supply. The MAX3171/MAX3173, along with the MAX3170 and MAX3172/MAX3174, form a complete software-selectable DTE or DCE interface port that supports the V.28 (RS-232), V.10/V.11 (RS-449, V.36, EIA530, EIA-530-A, X.21, RS-423), and V.35 protocols. The MAX3171/MAX3173 carry the control signals, while the MAX3170 transceiver carries the high-speed clock and data signals. The MAX3172/MAX3174 provide termination for the clock and data signals and have an extra transceiver for applications requiring four transceivers for control handshaking.
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+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceiver
No-Cable Mode
The MAX3171/MAX3173 enter no-cable mode when the mode select pins are left unconnected or tied HIGH (M0 = M1 = M2 = 1). In this mode, the multiprotocol drivers and receivers are disabled and the supply current is less than 8mA. The receiver outputs enter a highimpedance state in no-cable mode, which allows these output lines to be shared with other receivers (the receiver outputs have an internal pullup resistor to pull the outputs HIGH if not driven). Also, in no-cable mode, the transmitter outputs enter a high-impedance state, so these output lines can be shared with other devices.
Applications Information
Capacitor Selection
The capacitors used for the charge pumps, as well as the supply bypassing, should have a low-ESR and lowtemperature coefficient. Multilayer ceramic capacitors with an X7R dielectric offer the best combination of performance, size, and cost. The flying capacitors (C1, C2) should have a value of 1F, while the reservoir capacitors (C3, C4) and bypass capacitor (C5) should have a minimum value of 3.3F (Figure 5). To reduce the ripple present on the transmitter outputs, capacitors C3, C4, and C5 can be increased. Do not increase the value of C1 and C2.
MAX3171/MAX3173
Dual Charge-Pump Voltage Converter
The MAX3171/MAX3173 internal power supply consists of a regulated dual charge pump that provides positive and negative output voltages from a +3.3V supply. The charge pump operates in discontinuous mode: If the output voltage is less than the regulated voltage, the charge pump is enabled; if the output voltage exceeds the regulated voltage, the charge pump is disabled. Each charge pump requires a flying capacitor (C1, C2) and a reservoir capacitor (C3, C4) to generate the V+ and V- supplies. See Figure 5 for charge-pump connections. The charge pump is designed to supply V+ and Vpower to the MAX3172/MAX3174 in addition to the MAX3171/MAX3173 internal transceivers. Connect the MAX3172/MAX3174 V+ and V- terminals to the MAX3171/MAX3173 V+ and V- terminals, respectively.
Local Loopback Control Signal
For applications that require the use of local loopback (LL) signal routing, an extra transceiver is available for use on the MAX3172/MAX3174 multiprotocol termination network device.
Cable-Selectable Mode
Figure 6 shows a cable-selectable mulitprotocol interface. The mode control lines (M0, M1, M2, and DCE/DTE) are wired to the DB-25 connector. To select the serial interface mode, the appropriate combinations of M0, M1, M2, and DCE/DTE are grounded within the cable wiring. The control lines that are not grounded are pulled high by the internal pullups on the MAX3170. The serial interface protocol of the MAX3171/MAX3173 (MAX3170 and MAX3172/MAX3174) is now selected based on the cable connected to the DB-25 interface.
Fail-Safe
The MAX3171/MAX3173 guarantee a logic HIGH receiver output when the receiver inputs are shorted or open, or when they are connected to a terminated transmission line with drivers disabled. The V.11 receiver threshold is set between -25mV and -200mV to guarantee fail-safe operation. If the differential receiver input voltage (B - A) is -25mV, R_OUT is logic HIGH. In the case of a terminated bus with all transmitters disabled, the receiver's differential input voltage is pulled to 0 by the termination. With the MAX3171/MAX3173 receiver thresholds, this results in R_OUT logic HIGH with a 25mV (min) noise margin. The V.10 receiver threshold is set between +25mV and +300mV. If the V.10 receiver input voltage is +25mV, ROUT is logic HIGH. The V.28 receiver threshold is set between 0.8V and 2.0V. If the receiver input voltage is 0.8V, ROUT is logic HIGH. In the case of a terminated bus with transmitters disabled, the V.10/V.28 receiver's input voltage is pulled to ground by the termination. With the MAX3172/MAX3174 receiver thresholds, this results in R_OUT logic HIGH.
V.11 (RS-422) Interface
As shown in Figure 7, the V.11 protocol is a fully balanced differential interface. The V.11 driver generates 2V (min) between nodes A and B when 100 (min) resistance is presented at the load. The V.11 receiver is sensitive to 200mV differential signals at the receiver inputs A' and B'. The V.11 receiver input must comply with the impedance curve of Figure 8 and reject common-mode signals up to 7V developed across the cable (referenced from C to C' in Figure 7). The MAX3171/MAX3173 V.11 mode receiver has a differential threshold between -200mV and -25mV to ensure that the receiver has proper fail-safe operation (see Fail-Safe). To aid in rejecting system noise, the MAX3171/MAX3173 V.11 receiver has a 15mV (typ) hysteresis. Switch S3 in Figure 9 is open in V.11 mode to disable the V.28 5k termination at the inverting receiver input. Because the control signals are slow (64kbps), 100 termination resistance is generally not required for the MAX3171/MAX3173.
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+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers MAX3171/MAX3173
CTS(DTE) RTS(DCE) DSR(DTE) DTR(DCE) DTR(DTE) DSR(DCE) RTS(DTE) DCD(DTE) CTS(DCE) DCD(DCE) MAX3172 MAX3174 M0 M1 M2 DCE/DTE R4 D4 R3 R2 R1 RXD(DTE) TXD(DCE) RXC(DTE) SCTE(DCE) SCTE(DTE) RXC(DCE) TXC(DTE) TXD(DTE) TXC(DCE) RXD(DCE)
M0 M1 M2 DCE/DTE
VCC 13 5 DTE CTS B CTS A 10 8 DSR DSR 22 6 DCD DCD 23 20 19 4 DTR B DTR A RTS B RTS A 1 SHIELD 7 SG 18 21 M0 M1 25 DCE/DTE 16 3 9 17 12 15 11 24 14 2 RXC SCTE B RXC SCTE A TXC B TXC A TXD B TXD A RXD RXD
DB-25 CONNECTOR TXD B TXD A SCTE B SCTE A TXC B TXC A
DCE RTS B RTS A
DTR B DTR A
CABLE WIRING FOR MODE SELECTION MODE PIN 18 PIN 21 V.35 PIN 7 PIN 7 RS-449, V.36 N.C. PIN 7 RS-232 PIN 7 N.C.
CABLE WIRING FOR DCE/DTE SELECTION MODE PIN 25 DTE PIN 7 DCE N.C.
Figure 6. Cable-Selectable Multiprotocol DCE/DTE Port
CTS B CTS A
DCD DCD
DSR DSR
RXD RXD RXC RXC
V.10 Interface
GENERATOR BALANCED INTERCONNECTING CABLE LOAD CABLE RECEIVER TERMINATION A 100 MIN B C B C
A
Figure 7. Typical V.11 Interface 10
The V.10 interface (Figure 10) is an unbalanced singleended interface capable of driving a 450 load. The V.10 driver generates a 4V (min) VODO voltage across A' and C' when unloaded and a minimum of 0.9 VODO voltage with a 450 load. The V.10 receiver input trip threshold is defined between +300mV and -300mV with the input impedance characteristic shown in Figure 8. The MAX3171/MAX3173 V.10 mode receiver has a threshold between +25mV and +300mV to ensure that the receiver has proper fail-safe operation (see Fail-
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M0 M1 M2 DCE/DTE
MAX3171 MAX3173
R3
R2
R1
D3
D2
D1
D3
D2
D1
MAX3170
+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceiver MAX3171/MAX3173
IZ 3.25mA
A A R5 30k R8 5k R6 10k
-10V
-3V +3V VZ +10V
MAX3171 MAX3173
RECEIVER
-3.25mA
Figure 8. Receiver Input Impedance Curve
S3
A
A R5 30k R8 5k R6 10k
MAX3171 MAX3173
R7 10k B B R4 30k S5
RECEIVER
C GND S4
S3
Figure 11. V.10 Internal Resistance Network
R7 10k B B R4 30k
A
A R5 30k
C GND
MAX3171 MAX3173
R6 10k
R8 5k
Figure 9. V.11 Termination and Internal Resistance Networks
S3
RECEIVER
GENERATOR
UNBALANCED INTERCONNECTING CABLE
LOAD CABLE TERMINATION A
RECEIVER
R4 30k
R7 10k B B
A
C
C
C
GND
Figure 10. Typical V.10/V.28 Interface
Figure 12. V.28 Termination and Internal Resistance Networks
______________________________________________________________________________________
11
+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers MAX3171/MAX3173
CTS(DTE) RTS(DCE) DSR(DTE) DTR(DCE) DTR(DTE) DSR(DCE) RTS(DTE) DCD(DTE) CTS(DCE) DCD(DCE) MAX3172 MAX3174 M0 M1 M2 DCE/DTE MAX3171 MAX3173 R3 R2 R1 D3 D2 D1 R4 D4 R3 R2 R1 D3 D2 D1 RXD(DTE) TXD(DCE) LL(DTE) RXC(DTE) LL(DCE) SCTE(DCE) SCTE(DTE) RXC(DCE) TXC(DTE) TXD(DTE) TXC(DCE) RXD(DCE)
MAX3170 M0 M1 M2 DCE/DTE M0 M1 M2 DCE/DTE
M0 M1 M2 DCE/DTE
13 5 DTE CTS B CTS A
10 8 DSR B DSR A
22 6 DCD B DCD A
23 20 19 4 DTR B DTR A RTS B RTS A
1 SHIELD
7 18 SG LL A
16 3
9 17
12 15 11 24 14 2 TXC B TXC A RXC B SCTE B RXC A SCTE A TXD B TXD A RXD B RXD A
TXD B TXD A SCTE B SCTE A
DCE RTS B RTS A
DTR B DTR A
DSR B DSR A
DCD B DCD A
CTS B CTS A
LL A
Figure 13. Multiprotocol DCE/DTE Port
Safe). To aid in rejecting system noise, the MAX3171/MAX3173 V.10 receiver has 15mV (typ) hysteresis. Switch S3 in Figure 11 is open in V.10 mode to disable the 5k V.28 termination at the receiver input. Switch S4 is closed, and switch S5 is open to internally ground the receiver B input.
Figure 12 is closed in V.28 mode to enable the 5k V.28 termination at the receiver input.
Receiver Glitch Rejection
To facilitate operation in an unterminated or otherwise noisy system, the MAX3171 features 10s of receiver input glitch rejection in V.10, V.11, and V.28 modes. The glitch rejection circuitry blocks the reception of high-frequency noise (tB < 5s) while receiving a lowfrequency signal (tB > 15s), allowing glitch-free operation in unterminated systems at up to 64kbps. The MAX3173 does not have this feature and can be operated at data rates up to 240kbps if properly terminated.
V.28 Interface
The V.28 interface is an unbalanced single-ended interface (Figure 12). The V.28 generator provides 5V (min) across the load impedance between A' and C'. The V.28 standard specifies input trip points at 3V. The MAX3171/MAX3173 V.28 mode receiver has a threshold between +0.8V and +2.0V to ensure that the receiver has proper fail-safe operation (see Fail-Safe). To aid in rejecting system noise, the MAX3171/MAX3173 V.28 receiver has a 500mV (typ) hysteresis. Switch S3 in
12
DTE vs. DCE Operation
Figure 13 shows a DCE or DTE controller-selectable interface. The DCE/DTE input switches the port's mode of operation. A logic high selects DCE, which enables
______________________________________________________________________________________
TXC B TXC A
DB-25 CONNECTOR
RXD B RXD A RXC B RXC A
+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceiver MAX3171/MAX3173
DTE SERIAL CONTROLLER
MAX3170 MAX3172 MAX3174 MAX3172 MAX3174
DCE
MAX3170
SERIAL CONTROLLER
TXD SCTE
D1 D2 D3
TXD SCTE
103 103
R3 R2 R1
TXD SCTE
TXC RXC
R1 R2
103 103
TXC RXC RXD LL
D3 D2
TXC RXC
RXD LL
R3 D4
103
D1 R4 D4
RXD LL
R4
MAX3171 MAX3173
MAX3171 MAX3173
RTS DTR
D1 D2 D3
RTS DTR
R3 R2 R1
RTS DTR
DCD DSR
R1 R2
DCD DSR CTS
D3 D2
DCD DSR
CTS
R3
D1
CTS
Figure 14. DCE-to-DTE X.21 Interface
driver 3 on the MAX3171/MAX3173, driver 3 on the MAX3170, and driver 4 on the MAX3172/MAX3174. A logic low selects DTE, which enables receiver 1 on the MAX3171/MAX3173, receiver 1 on the MAX3170, and receiver 4 on the MAX3172/MAX3174. This application requires only one DB-25 connector. See Figure 13 for complete signal routing in DCE and DTE modes. For example, driver 3 routes the DCD (DCE) signal to pins 22 and 6 in DCE mode, while in DTE mode, receiver 1 routes pins 22 and 6 to DCD (DTE).
Complete Multiprotocol X.21 Interface
Figure 14 shows a complete DCE-to-DTE interface operating in X.21 mode. The MAX3171/MAX3173 generate the control signals, and the MAX3170 is used to generate the clock and data signals. The MAX3172/ MAX3174 generate local loopback and are used to terminate the clock and data signals to support the V.11 protocol for cable termination. The control signals do not need external termination.
______________________________________________________________________________________
13
+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceivers MAX3171/MAX3173
Compliance Testing
A European Standard EN 45001 test report is available for the MAX3170-MAX3174 chipset. A copy of the test report will be available from Maxim.
TOP VIEW
V+ 1 C2+ 2 C2- 3 28 C1+ 27 VCC 26 GND 25 C124 T1OUTA
Pin Configuration
Chip Information
TRANSISTOR COUNT: 1763 PROCESS: BiCMOS
V- 4 T1IN 5 T2IN 6 T3IN 7 R1OUT 8 R2OUT 9 R3OUT 10 M0 11 M1 12 M2 13 DCE/DTE 14
MAX3171 MAX3173
23 T1OUTB 22 T2OUTA 21 T2OUTB 20 T3OUTA/R1INA 19 T3OUTB/R1INB 18 R2INB 17 R2INA 16 R3INA 15 R3INB
SSOP
14
______________________________________________________________________________________
+3.3V Multiprotocol 3Tx/3Rx Software-Selectable Control Transceiver
Package Information
SSOP.EPS
MAX3171/MAX3173
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15 (c) 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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