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19-1703; Rev 0; 4/00
+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver
General Description
The MAX3170 is a three-driver/three-receiver multiprotocol transceiver that operates from a +3.3V single supply. The MAX3170, along with the MAX3171/MAX3173 and MAX3172/MAX3174, form a complete softwareselectable data terminal equipment (DTE) or data communications equipment (DCE) interface port that supports the V.28 (RS-232), V.11 (RS-449/V.36, EIA530, EIA530-A, X.21), and V.35 protocols. The MAX3170 transceiver carries the high-speed clock and data signals, while the MAX3171 or MAX3173 carries the control signals. The MAX3170 can be terminated by the MAX3172 or MAX3174 software-selectable resistor termination network or by a discrete termination network. An internal charge pump and proprietary low-dropout transmitter output stage allow V.11-, V.28-, and V.35compliant operation from a +3.3V single 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 1mA and all transmitter and receiver outputs are disabled (high impedance). Short-circuit limiting and thermal shutdown circuitry protect the drivers against excessive power dissipation. o 3V/5V Logic-Compatible I/O o Certified TBR-1 and TBR-2 Compliant (NET1 and NET2)--Pending Completion o Supports V.28 (RS-232), V.11 (RS-449/V.36, EIA530, EIA530-A, X.21), and V.35 Protocols o Software-Selectable DTE/DCE o Complete DTE/DCE Port with MAX3171/MAX3173 and MAX3172/MAX3174 o True Fail-Safe Receiver Operation o Available in Small 28-Pin SSOP Package o 10Mbps Operation (V.11/V.35) o Requires Only Four Tiny Surface-Mount Capacitors o All Transmitter Outputs Are Fault Protected to 15V to Survive Cable Miswiring
Features
o Industry's First +3.3V Single-Supply Transceiver
MAX3170
________________________Applications
Data Networking CSU and DSU Data Routers PCI Cards Telecommunications
PART MAX3170CAI
Ordering Information
TEMP. RANGE 0C to +70C PIN-PACKAGE 28 SSOP
Pin Configuration appears at end of data sheet.
Typical Operating Circuit
CTS DSR DCD DTR RTS LL 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, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
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 MAX3170CAI .....................................................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 = 3.3F, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C and VCC = +3.3V.)
PARAMETER DC CHARACTERISTICS V.11 mode V.11 mode with no load Supply Current (DCE Mode) (Digital Inputs = GND or VCC) (All Outputs Static) V.35 mode ICC V.35 mode with no load V.28 mode V.28 mode with no load No-cable mode V.11 mode, full load Internal Power Dissipation (DCE Mode) PD V.35 mode, full load V.28 mode, full load V.11 mode V+ Output Voltage (DCE Mode) (Full Load) V+ V.35 mode V.28 mode No-cable mode V.11 mode V- Output Voltage (DCE Mode) (Full Load) Charge-Pump Enable Time LOGIC INPUTS (M0, M1, M2, DCE/DTE, T_IN) Input High Voltage Input Low Voltage Logic Input Current VIH VIL IIN IIH IIL T_IN M0, M1, M2, DCE/DTE = VCC M0, M1, M2, DCE/DTE = GND 30 50 2.0 0.8 1 1 100 A V V VV.35 mode V.28 mode No-cable mode Delay until V+ and V- specifications met -4.25 1 ms 4 4.25 5.55 5 -4.1 -3.7 -5.45 V V 190 3 160 20 10 4 0.8 410 510 15 mW 250 7 210 40 20 7 2 mA SYMBOL CONDITIONS MIN TYP MAX UNITS
2
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+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.3V 5%, C1 = C2 = 1F, C3 = C4 = 3.3F, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C and VCC = +3.3V.)
PARAMETER LOGIC OUTPUTS (R_OUT) Output High Voltage Output Low Voltage Rise or Fall Time Output Leakage Current (Receiver Output Tristated) TRANSMITTER OUTPUTS Output Leakage Current Data Rate RECEIVER INPUTS Receiver Input Resistance RIN -10V < VA,B < +10V, VA or VB grounded (V.11/V.35/no-cable mode) -15V < VA < +15V (V.28 mode) Data Rate V.11 TRANSMITTER Unloaded Differential Output Voltage Loaded Differential Output Voltage Change in Magnitude of Output 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 Output V.11 RECEIVER Differential Threshold Voltage Input Hysteresis Receiver Input to Output Data Skew VTH VTH tPHL, tPLH |tPHL - tPLH| -7V < VCM < +7V -7V < VCM < +7V VCM = 0, Figure 2 VCM = 0, Figure 2 -200 -100 15 60 5 120 16 -25 mV mV ns ns VODO R = 1.95k, Figure 1 4.0 2.0 0.5 x VODO 0.2 3.0 0.2 60 10 50 2 2 2 150 25 80 10 6.0 V V.11/ V.35 mode V.28 mode 20 3 40 5 10 240 7 Mbps kbps k IZ -0.25V < VOUT < +0.25V power-off or no-cable mode V.11/ V.35 mode V.28 mode 10 240 100 A Mbps kbps VOH VOL tr, tf ISOURCE = 1.0mA ISINK = 1.6mA 10% to 90% 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
MAX3170
VODL VOD VOC VOC ISC tr, tf tPHL, tPLH |tPHL - tPLH| tSKEW
R = 50, Figure 1 R = 50, Figure 1 R = 50, Figure 1 R = 50, Figure 1 VOUT = GND 10% to 90%, Figure 2 Figure 2 Figure 2 Figure 2
V V V V mA ns ns ns ns ns
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+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.3V 5%, C1 = C2 = 1F, C3 = C4 = 3.3F, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C and VCC = +3.3V.)
PARAMETER V.35 TRANSMITTER Differential Output Voltage Output High Current Output Low Current Rise or Fall Time Transmitter Input to Output Data Skew Output-to-Output Skew Channel-to-Channel Output Skew V.35 RECEIVER Differential Input Voltage Input Hysteresis Receiver Input to Output Data Skew V.28 TRANSMITTER Output Voltage Swing Short-Circuit Current VO ISC RL = 3k, CL = 2500pF, measured from +3V to -3V or -3V to +3V, Figure 4 Output Slew Rate SR RL = 7k, CL = 150pF, measured from +3V to -3V or -3V to +3V, Figure 4 Transmitter Input to Output Data Skew V.28 RECEIVER Input Threshold Low Input Threshold High Input Hysteresis Data Skew VIL VIH VHYS |tPHL - tPLH| Figure 5 Figure 5 Figure 5 0.8 1.1 1.6 0.5 100 2.0 V V V ns tPHL, tPLH |tPHL - tPLH| Figure 4 Figure 4 6 1 100 30 s ns 4 All transmitters loaded with RL = 3k No load 25 5.0 5.4 6.5 60 30 V/s V mA VTH VTH tPHL, tPLH |tPHL - tPLH| -4V < VCM < +4V, Figure 3 -4V < VCM < +4V, Figure 3 VCM = 0 VCM = 0 -200 -100 15 70 5 120 16 -25 mV mV ns ns IOH IOL tr, tf tPHL, tPLH |tPHL - tPLH| -4V < VCM < +4V, Figure 3 VA, B = 0 VA, B = 0 10% to 90%, Figure 3 Figure 3 Figure 3 Figure 3 0.44 9 -13 0.55 11 -11 10 50 5 2 2 80 10 0.66 13 -9 V mA mA ns ns ns ns ns SYMBOL CONDITIONS MIN TYP MAX UNITS
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+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver
Typical Operating Characteristics
(VCC = +3.3V, C1 = C2 = 1.0F, C3 = C4 = 3.3F, TA = +25C, unless otherwise noted.)
V.11 SUPPLY CURRENT vs. DATA RATE
MAX3170-01
MAX3170
V.28 SUPPLY CURRENT vs. DATA RATE
MAX3170-02
V.35 SUPPLY CURRENT vs. DATA RATE
DCE MODE, VCM = 0 ALL TRANSMITTERS OPERATING AT SPECIFIED RATE
MAX3170-03
250
V.11 SUPPLY CURRENT (mA)
V.28 SUPPLY CURRENT (mA)
V.35 SUPPLY CURRENT (mA)
200
DCE MODE, R = 50 ALL TRANSMITTERS OPERATING AT SPECIFIED RATE
100
80
DCE MODE, ALL TRANSMITTERS OPERATING AT THE SPECIFIED DATA RATE RL = 3k, CL = 2000pF
200
150
150
60
100
100
40
50
20
50
0 0.1 1 10 100 1000 10,000 DATA RATE (kbps)
0 0 50 100 150 200 250 DATA RATE (kbps)
0 0.1 1 10 100 1000 10,000 DATA RATE (kbps)
V.11 DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE
MAX3170-04
V.28 OUTPUT VOLTAGE vs. TEMPERATURE
8 7 6 5 4 3 2 1 0 -1 -2 -3 -4 -5 -6 -7 -8 DCE MODE, R = 3k VOUT+
MAX3170-05
V.35 DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE
DIFFERENTIAL OUTPUT VOLTAGE (V) DCE MODE, VCM = 0 VOH
MAX3170-06
4 DRIVER DIFFERENTIAL OUTPUT VOLTAGE (V) 3 2 1 0 -1 -2
DCE MODE, R = 50 VOH
0.66 0.44 0.22 0 -0.22 -0.44 -0.66
OUTPUT VOLTAGE (V)
VOL -3 -4 -40 -20 0 20 40 60 80 TEMPERATURE (C)
VOUT-
VOL
-40
-20
0
20
40
60
80
-40
-20
0
20
40
60
80
TEMPERATURE (C)
TEMPERATURE (C)
V.35 DIFFERENTIAL OUTPUT VOLTAGE vs. COMMON-MODE VOLTAGE
MAX3170-07
V.11/V.35 RECEIVER INPUT CURRENT vs. INPUT VOLTAGE
MAX3170-08
V.28 RECEIVER INPUT CURRENT vs. INPUT VOLTAGE
2.0 RECEIVER INPUT CURRENT (mA) 1.5 1.0 0.5 0 -0.5 -1.0 -1.5 -2.0 DCE MODE
MAX3170-09
570 DIFFERENTIAL OUTPUT VOLTAGE (V)
300 RECEIVER INPUT CURRENT (A) 200 100 0 -100 -200 -300
2.5
DCE MODE
560 VOH 550
540
530
520 -4 -3 -2 -1 0 VCM (V) 1 2 3 4
-2.5 -10 -8 -6 -4 -2 0 2 4 6 8 10 -10 -8 -6 -4 -2 0 2 4 6 8 10 INPUT VOLTAGE (V) INPUT VOLTAGE (V)
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+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
Typical Operating Characteristics (continued)
(VCC = +3.3V, C1 = C2 = 1.0F, C3 = C4 = 3.3F, TA = +25C, unless otherwise noted.)
V.11 LOOPBACK SCOPE PHOTO
MAX3170-10
V.28 LOOPBACK SCOPE PHOTO
MAX3170-11
V.35 LOOPBACK SCOPE PHOTO
MAX3170-12
2V/div
TIN
TIN
TIN
TOUT/RIN
TOUT/RIN
TOUT/RIN
2V/div
50ns/div
1s/div
50ns/div
V.28 SLEW RATE vs. LOAD CAPACITANCE
MAX3170-13
V.11 TRANSMITTER PROPAGATION DELAY vs. TEMPERATURE
MAX3170-14
V.11 RECEIVER PROPAGATION DELAY vs. TEMPERATURE
70 PROPAGATION DELAY (ns) 60 50 40 30 20 10 0 tPHL
MAX3170-15
16 14 12 SLEW RATE (V/s) 10 8 6 4 2 0 0 1000 2000 3000 4000 RL = 3k 1 TRANSMITTER SWITCHING AT 250kbps; OTHER TRANSMITTERS SWITCHING AT 15kbps -SLEW +SLEW
60 50 PROPAGATION DELAY (ns) 40 30 20 10 0 tPHL tPLH
80 tPLH
5000
-40
-20
0
20
40
60
80
-40
-20
0
20
40
60
80
LOAD CAPACITANCE (pF)
TEMPERATURE (C)
TEMPERATURE (C)
V.35 TRANSMITTER PROPAGATION DELAY vs. TEMPERATURE
MAX3170-16
V.35 RECEIVER PROPAGATION DELAY vs. TEMPERATURE
tPLH 70 PROPAGATION DELAY (ns) 60 50 40 30 20 10 0 tPHL
MAX3170-17
60 50 PROPAGATION DELAY (ns) 40 30 20 10 0 -40 -20 0 20 40 60 80 TEMPERATURE (C) tPHL tPLH
80
-40
-20
0
20
40
60
80
TEMPERATURE (C)
6
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2V/div
ROUT
ROUT
ROUT
400mV/div
2V/div
5V/div
2V/div
+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver
Test Circuits
MAX3170
100pF
R VOD
100 50pF
R
VOC
100pF
Figure 1. V.11 DC Test Circuit
Figure 2. V.11 AC Test Circuit
50 125 VCM 125
50
50
50
50pF
Figure 3. V.35 Transmitter/Receiver Test Circuit
CL
RL 50pF
Figure 4. V.28 Driver Test Circuit
Figure 5. V.28 Receiver Test Circuit
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+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
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. 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. Bypass V- to ground with a 3.3F ceramic capacitor. Transmitter CMOS Inputs (T1IN, T2IN, T3IN) Receiver CMOS Outputs (R1OUT, R2OUT, R3OUT) Mode Select Pins (M0, M1, M2). Internally pulled up to VCC. See Table 1 for detailed information. DCE/DTE Mode Select Pin. 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 V CC to ground with a 3.3F capacitor. Positive Terminal of the Voltage-Doubler Charge-Pump Capacitor. Connect C1+ to C1- with a 1F ceramic capacitor.
Detailed Description
The MAX3170 is a three-driver/three-receiver multiprotocol transceiver that operates from a +3.3V single supply. The MAX3170, along with the MAX3171/MAX3173 and MAX3172/MAX3174, form a complete softwareselectable DTE or DCE interface port that supports the V.28 (RS-232), V.11 (RS-449/V.36, EIA530, EIA530-A, and X.21), and V.35 protocols. The MAX3170 transceiver carries the high-speed clock and data signals, while the MAX3171 or MAX3173 carries the control signals.
The MAX3170 can be terminated by the MAX3172 or MAX3174 software-selectable resistor termination network or by a discrete termination network. The MAX3170 features a 1mA no-cable mode, true failsafe 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 high-impedance state.
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+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
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.35 V.11 V.28 Z V.11 V.11 V.11 V.11 V.35 V.11 V.28 Z TRANSMITTERS T2 V.11 V.11 V.11 V.11 V.35 V.11 V.28 Z V.11 V.11 V.11 V.11 V.35 V.11 V.28 Z T3 Z Z Z Z Z Z Z Z V.11 V.11 V.11 V.11 V.35 V.11 V.28 Z R1 V.11 V.11 V.11 V.11 V.35 V.11 V.28 Z Z Z Z Z Z Z Z Z RECEIVERS R2 V.11 V.11 V.11 V.11 V.35 V.11 V.28 Z V.11 V.11 V.11 V.11 V.35 V.11 V.28 Z R3 V.11 V.11 V.11 V.11 V.35 V.11 V.28 Z V.11 V.11 V.11 V.11 V.35 V.11 V.28 Z
Z = High impedance
Mode Selection
The state of the 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 transceiver will be configured as a DTE 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 a logic HIGH if left unconnected. The MAX3170'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 V CC (logic HIGH). If the M0, M1, and M2 mode inputs are all unconnected, the MAX3170 will enter nocable mode and the supply current will drop to 1mA.
1mA. The receiver outputs enter a high-impedance state in no-cable mode, which allows these output lines to be shared with other receivers (the receiver outputs have an internal pull-up resistor to pull the outputs HIGH if not driven). Also, in no-cable mode, the transmitter outputs enter a high-impedance state so that these output lines can be shared with other devices.
Dual Charge-Pump Voltage Converter
The MAX3170's 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 6 for charge-pump connections.
No-Cable Mode
The MAX3170 will 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 drops to
Fail-Safe Receivers
The MAX3170 guarantees a logic-high receiver output when the receiver inputs are shorted or open, or when they are connected to a terminated transmission line with all drivers disabled. This is done by setting the
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+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
receiver threshold between -25mV and -200mV in the V.11 and V.35 modes. If the differential receiver input voltage (B - A) is -25mV, R_OUT is logic HIGH. If (B A) is -200mV, R_OUT is logic LOW. In the case of a terminated bus with all transmitters disabled, the receiver's differential input voltage is pulled to zero by the termination. With the receiver thresholds of the MAX3170, this results in a logic HIGH with a 25mV minimum noise margin.
1 C3 3.3F C2 1F 2 3 4 C4 3.3F
MAX3170
V+ C2+ C2VC1+ VCC GND C1-
28 27 26 25 C5 3.3F C1 1F
Applications Information
Capacitor Selection
The capacitors used for the charge pumps, as well as the supply bypassing, should have a low equivalent series resistance (ESR) and low temperature 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 6). To reduce the ripple present on the transmitter outputs, capacitors C3, C4, and C5 can be increased. The values of C1 and C2 should not be increased.
Figure 6. Charge-Pump Connections
V.11 (RS-422) Interface
As shown in Figure 8, the V.11 protocol is a fully balanced differential interface. The V.11 driver generates a minimum of 2V between nodes A and B when a 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 rejects common-mode signals developed across the cable (referenced from C to C) of up to 7V, allowing for error-free reception in noisy environments. The receiver inputs must comply with the impedance curve shown in Figure 9. For high-speed data transmission, the V.11 specification recommends terminating the cable at the receiver with a 100 minimum resistor. This resistor, although not required, prevents reflections from corrupting transmitted data. In Figure 10, the MAX3172 or MAX3174 is used to terminate the V.11 receiver. Internal to the MAX3172/MAX3174, S1 is closed and S2 is open to present a 100 minimum differential resistance. The MAX3170's internal V.28 termination is disabled by opening S3.
Cable Termination
The MAX3172/MAX3174 software-selectable resistor network is designed to be used with the MAX3170. The MAX3172/MAX3174 multiprotocol termination network provides V.11- and V.35-compliant termination, while V.28 receiver termination is internal to the MAX3170. These cable termination networks provide compatibility with V.11, V.28, and V.35 protocols. Using the MAX3172/MAX3174 termination network provides the advantage of not having to build expensive termination networks out of resistors and relays, manually changing termination modules, or building termination networks into custom cables.
Cable-Selectable Mode
A cable-selectable multiprotocol interface is shown in Figure 7. The mode control lines M0, M1, and DCE/DTE are wired to the DB-25 connector. To select the serial interface mode, the appropriate combination 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 pull-ups on the MAX3170. The serial interface protocol of the MAX3170 (and MAX3171/MAX3173 and MAX3172/MAX3174) is selected based on the cable that is connected to the DB-25 interface.
V.35 Interface
Figure 11 shows a fully balanced differential standard V.35 interface. The generator and the load must both present a 100 10 differential impedance and a 150 15 common-mode impedance as shown by the resistive T-networks in Figure 11. The V.35 driver generates a current output (11mA typ) that develops an output voltage of 550mV across the generator and load termination networks. The V.35 receiver is sensitive to 200mV differential signals at the receiver inputs A and B. The V.35 receiver rejects common-mode signals developed across the cable (referenced from C to C) of up to 4V, allowing for error-free reception in noisy environments.
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+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
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 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
RXC B SCTE B RXC A SCTE A
TXC B TXC A
TXD B TXD A SCTE B SCTE A
DTR B DTR A
DCE RTS B RTS A
DCD B DCD A
DSR B DSR A
CTS B CTS A
TXC B TXC 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. NO CABLE N.C. N.C.
CABLE WIRING FOR DCE/DTE SELECTION MODE PIN 25 DTE PIN 7 DCE N.C.
Figure 7. Cable-Selectable Multiprotocol DCE/DTE Port
In Figure 12, the MAX3172 or MAX3174 is used to implement the resistive T-network that is needed to properly terminate the V.35 driver and receiver. Internal to the MAX3172/MAX3174, S1 and S2 are closed to connect the T-network resistors to the circuit. The V.28 termination resistor (internal to the MAX3170) is disabled by opening S3 to avoid interference with the Tnetwork impedances.
V.28 Interface
The V.28 interface is an unbalanced single-ended interface (Figure 13). The V.28 driver generates a minimum
of 5V across the load impedance between A and C. The V.28 receiver has a single-ended input and does not reject any common-mode differences between C and C. The V.28 receiver has input trip points at 3V. To aid in rejecting system noise, the MAX3170 V.28 receiver has a typical hysteresis of 0.5V. Figure 14 shows that the MAX3172/MAX3174 termination network is disabled by opening S1 and S2. The MAX3170's internal 5k V.28 termination is enabled by closing S3.
______________________________________________________________________________________
RXD B RXD A
DB-25 CONNECTOR
RXD B RXD A RXC B RXC A
TXD B TXD A
18 21 M0 M1
25 DCE/DTE
16 3
9 17
12 15 11 24 14 2
M0 M1 M2 DCE/DTE
MAX3171 MAX3173
R3
R2
R1
D3
D2
D1
D3
D2
D1
MAX3170
11
+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
GENERATOR BALANCED INTERCONNECTING CABLE IZ LOAD CABLE TERMINATION A A 100 MIN B C B C RECEIVER -10V -3V +3V VZ +10V 3.25mA
-3.25mA
Figure 9. Receiver Input Impedance Curve
Figure 8. Typical V.11 Interface
A
A R5 30k R1 51.5
MAX3170
MAX3172 MAX3174
R8 5k
R6 10k
RECEIVER
S1 S2
S3 R3 124
R2 51.5 B B R4 30k
R7 10k
C GND
Figure 10. V.11 Termination and Internal Resistance Networks
GENERATOR
BALANCED INTERCONNECTING CABLE A A CABLE TERMINATION
LOAD RECEIVER
50
125
125
50
50 B C B C
50
Figure 11. Typical V.35 Interface 12 ______________________________________________________________________________________
+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
A A R5 30k R1 51.5
MAX3170
MAX3172 MAX3174
R8 5k
R6 10k
RECEIVER
S1
S3 R3 124 S2 R2 51.5 R7 10k B R4 30k
B
C GND
Figure 12. V.35 Termination and Internal Resistance Networks
GENERATOR
UNBALANCED INTERCONNECTING CABLE
LOAD CABLE TERMINATION A
RECEIVER
A
This application requires only one DB-25 connector, but separate cables for DCE or DTE signal routing. See Figure 15 for complete signal routing in DCE and DTE modes. For example, the MAX3170's D3 routes the TXC (DCE) signal to pins 12 and 15 in DCE mode, while in DTE mode, the MAX3170's R1 routes pins 12 and 15 to TXC (DTE).
Complete Multiprotocol X.21 Interface
C C
Figure 13. Typical V.28 Interface
DTE vs. DCE Operation
Figure 15 shows a DCE or DTE controller-selectable interface. The DCE/DTE pin (pin 14) switches the port's mode of operation. A logic HIGH selects DCE, which enables D3 on the MAX3170, D3 on the MAX3171/ MAX3173, and D4 on the MAX3172/MAX3174. A logic LOW selects DTE, which enables R1 on the MAX3170, R1 on the MAX3171/MAX3173, and R4 on the MAX3172/ MAX3174.
A complete DTE-to-DCE interface operating in X.21 mode is shown in Figure 16. The MAX3170 is used to generate the clock and data signals, and the MAX3171/MAX3173 generate the control signals. The MAX3172/MAX3174 generate local loopback (LL), 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.
Compliance Testing
A European Standard EN 45001 test report is available for the MAX3170/MAX3171/MAX3173/MAX3172/ MAX3174 chipset. A copy of the test report will be available from Maxim upon completion.
______________________________________________________________________________________
13
+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
A A R5 30k R1 51.5
MAX3170
MAX3172 MAX3174
R8 5k
R6 10k
RECEIVER
S1 S2
S3 R3 124
R2 51.5 B B R4 30k
R7 10k
C GND
Figure 14. V.28 Termination and Internal Resistance Networks
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
RXD(DTE) TXD(DCE) LL(DTE) RXC(DTE) LL(DCE) SCTE(DCE)
SCTE(DTE) RXC(DCE) TXC(DTE) TXD(DTE) TXC(DCE) RXD(DCE)
R4 D4
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 RXC B SCTE B RXC A SCTE A TXC B TXC A TXD B TXD A RXD B RXD A
TXD B TXD A SCTE B SCTE A
DTR B DTR A
DCE RTS B RTS A
DCD B DCD A
DSR B DSR A
CTS B CTS A
LL A
Figure 15. Multiprotocol DCE/DTE Port 14 ______________________________________________________________________________________
TXC B TXC A
DB-25 CONNECTOR
RXD B RXD A RXC B RXC A
M0 M1 M2 DCE/DTE
M0 M1 M2 DCE/DTE
MAX3171 MAX3173
R3
R2
R1
D3
D2
D1
R3
R2
R1
D3
D2
D1
MAX3170
+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
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 16. DCE-to-DTE X.21 Interface
______________________________________________________________________________________
15
+3.3V, Multiprotocol, 3 Tx/3 Rx, SoftwareSelectable Clock/Data Transceiver MAX3170
Pin Configuration
TOP VIEW
V+ 1 C2+ 2 C2- 3 V- 4 T1IN 5 T2IN 6 T3IN 7 R1OUT 8 R2OUT 9 R3OUT 10 M0 11 M1 12 M2 13 DCE/DTE 14 28 C1+ 27 VCC 26 GND 25 C124 T1OUTA
Chip Information
TRANSISTOR COUNT: 4058
MAX3170
23 T1OUTB 22 T2OUTA 21 T2OUTB 20 T3OUTA/R1INA 19 T3OUTB/R1INB 18 R2INB 17 R2INA 16 R3INA 15 R3INB
28 SSOP
Package Information
SSOP.EPS
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.
16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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