MAXIM MAX3172, MAX3174 User Manual

General Description

The MAX3172/MAX3174 contain five software-selec­table multiprotocol cable termination networks. Each
network is capable of terminating V.11 (RS-422, RS­530, RS-530A, RS-449, V.36, and X.21) with a 100Ω dif­ferential load, V.35 with a T-network load, or V.28
(RS-232) and V.10 (RS-423) with an open circuit load
for use with transceivers having on-chip termination.
The devices replace discrete resistor termination net­works and expensive relays required for multiprotocol
termination. The MAX3172/MAX3174, along with the
MAX3170 and MAX3171/MAX3173, form a complete
+3.3V software-selectable DTE or DCE interface port
supporting V.11/RS-422, RS-530, RS-530A, V.36/RS­449, V.35, V.28/RS-232, V.10/RS-423, and X.21 serial
interfaces.

In addition to the five multiprotocol cable termination
networks, the MAX3172/MAX3174 contain a 1Tx/1Rx
multiprotocol transceiver designed to use V+ and V­generated by the MAX3171/MAX3173 charge pump.
The MAX3172/MAX3174 transceiver is software selec­table between V.10 and V.28 modes of operation. The
MAX3172 features 10µs deglitching on the V.10/V.28
receiver input to facilitate unterminated operation, while
the MAX3174 is used in applications that do not require
deglitching on the serial handshake signals. These
devices are available in a 28-pin SSOP package.

________________________Applications

Data Networking PCI Cards
CSU and DSU Telecommunications
Data Routers

Features

♦ Industry’s First +3.3V Multiprotocol Termination

Networks and Transceivers

♦ Certified TBR-1 and TBR-2 Compliant

(NET1 and NET2)

♦ Support V.28 (RS-232), V.11 (RS-422, RS-530, RS-

530A, RS-449, V.36, and X.21), V.10 and V.35

♦ 3V/5V Logic-Compatible I/O
♦ Software-Selectable DTE/DCE
♦ Replace Discrete Resistor Termination Networks

and Expensive Relays

♦ 10µs Receiver Input Deglitching (MAX3172 only)
♦ Available in Small 28-Pin SSOP Package
♦ Transmitter Output Fault Protected to ±15V,

Tolerates Cable Miswiring

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

________________________________________________________________ Maxim Integrated Products 1

19-1801; Rev 2; 6/04

Ordering Information

Typical Operating Circuit

Pin Configuration appears at end of data sheet.

For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

PART TEMP RANGE PIN-PACKAGE

MAX3172CAI 0°C to +70°C 28 SSOP

MAX3172EAI -40°C to +85°C 28 SSOP

MAX3174CAI 0°C to +70°C 28 SSOP

CTS DSR RTSDTR LLDCD

MAX3171
MAX3173

R2R3

13 5 10 8 22 6 23 20 19 4 1 7 1618 3 9 17 12 15 11 24 14 2

CTS B

CTS A

DSR B

DSR A

D3

R1

DCD B

DCD A

D2

DTR B

DTR A

D1

RTS B

RTS A

SHIELD

MAX3172
MAX3174

SG

DB-25 CONNECTOR

RXD RXC TXDTXC SCTE

D3

R1

R2R3

R4

D4

LL A

RXD B

RXD A

RXC B

RXC A

TXC B

TXC A

SCTE B

SCTE A

D1D2

TXD B

MAX3170

TXD A

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3.3V ± 5%, TA= T

MIN

to T

MAX

. Typical values are at VCC= +3.3V, TA= +25°C, unless otherwise noted. See Note 2 for V+

and V- input voltage conditions.)

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.

Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.

(All voltages referenced to GND unless otherwise noted.)
Supply Voltages

V

CC

......................................................................-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, INVERT, T4IN ................-0.3V to +6V

Logic Output Voltages

R4OUT...................................................-0.3V to (V

CC

+ 0.3V)

Short-Circuit Duration............................................Continuous

Transmitter Outputs

T4OUT ................................................................-15V to +15V

Short-Circuit Duration ........................................................60s

Receiver Input

R4INA .................................................................-15V to +15V

Termination Network Inputs (applied individually)

R_A, R_B ............................................................-15V to +15V

Continuous Power Dissipation (T

A

= +70°C)

28-Pin SSOP (derate 9.52mW/°C above +70°C) ........762mW

Operating Temperature Range

MAX3172CAI/MAX3174CAI...............................0°C to +70°C

MAX3172EAI...................................................-40°C to +85°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

DC CHARACTERISTICS

Supply Current
(Digital Inputs = GND or V

V+ Supply Current
(T4IN = GND)

V- Supply Current
(T4IN = V

TERMINATOR NETWORKS (R_A, R_B)
Differential-Mode Impedance

V.35 Mode
Common-Mode Impedance

V.35 Mode
Differential-Mode Impedance

V.11 Mode

Network OFF Impedance I

LOGIC INPUTS (M0, M1, M2, INVERT, DCE/DTE, T4IN)
Input High Voltage V
Input Low Voltage V
Logic Input Current IIH, I

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

)

CC

CC

I

I

CC

V+

I

V-

Z

IH
IL

)

All modes V.10 receiver inactive 80 200
All modes V.10 receiver active 400 750
No-cable mode
V.10/V.11/V.28/V.35 modes unloaded 0.5 2.5
V.10/V.11 modes T4OUT loaded 11.0 14.0
V.28/V.35 modes T4OUT loaded 3.0 5.0
No-cable mode -0.4 -1.0
V.10/V.11/V.28/V.35 modes unloaded -0.8 -2.5

V.10/V.11 modes T4OUT loaded -11.0 -14.0
V.28/V.35 modes T4OUT loaded -3.0 -5.0

Figure 1, -2V ≤ V

Figure 2, -2V ≤ V

Figure 1, -7V ≤ V

Switches open, -15V ≤ VA ≤ +15V, V

= GND or V

V

B

VIN = VCC or GND ±1 µA

IL

0.2 1.0

≤ +2V 90 104 110 Ω

CM

≤ +2V 135 153 165 Ω

CM

≤ +7V 100 104 110 Ω

CM

= VA,

B

floating

B

50 150 kΩ

2.0 V

0.8 V

µA

mA

mA

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V ± 5%, TA= T

MIN

to T

MAX

. Typical values are at VCC= +3.3V, TA= +25°C, unless otherwise noted. See Note 2 for V+

and V- input voltage conditions.)

LOGIC OUTPUT (R4OUT)
Output High Voltage V
Output Low Voltage V
Rise or Fall Time tr, t

Output Leakage Current
(Receiver Output Three-Stated)

TRANSMITTER OUTPUT (T4OUT)

Output Leakage Current I

Data Rate V.10/V.28 240 kbps
RECEIVER INPUT (R4INA)

Receiver Glitch Rejection
(MAX3172 only)

Receiver Input Resistance R

Data Rate

V.10 TRANSMITTER

Output Voltage Swing V
Loaded Output Voltage Swing V
Short-Circuit Current I

Rise or Fall Time tr, t

Transmitter Propagation Delay t

Data Skew

V.10 RECEIVER

Threshold Voltage V
Input Hysteresis ∆V

Receiver Propagation Delay t

Data Skew

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

PHL

| t

PHL

| t

ODO

PHL

t

PLH

PHL

t

PLH

OH
OL

Z

IN

ODL

SC

, t

TH

TH

, t

I
I
10% to 90%, CL = 15pF 15 ns

f

R4OUT = GND 30 50 100
R4OUT = V

-0.25V < V
power-off or no-cable mode

Minimum pulse width passed 5
Maximum pulse width rejected 15
V.10 enabled, -10V ≤ V
V.28 enabled, -15V ≤ V
MAX3172 64
MAX3174 240

RL = 3.9kΩ, Figure 3 ±4.0 ±4.4 ±6.0 V
RL = 450Ω, Figure 3 0.9 × V
T4OUT = GND ±100 ±150 mA

10% to 90%, RL = 450Ω, CL = 100pF,

f

Figure 3

PLHRL

­R

|

Figure 4

PLH

­Figure 4

|

= 1.0mA V

SOURCE

= 1.6mA 0.4 V

SINK

CC

< +0.25V,

T4OUT

≤ +10V 20 40

R4INA

≤ +15V 3 5 7

R4INA

= 450Ω, CL = 100pF, Figure 3 2 µs

= 450Ω, CL = 100pF, Figure 3 50 ns

L

MAX3172 5 10 15 µs
MAX3174 60 120 ns
MAX3172CAI 0.5 4
MAX3172EAI 0.5 5
MAX3174 5 16 ns

- 1.0 V

CC

0.1 1

-100 100 µA

ODO

2µs

25 100 250 mV

15 mV

µA

µs

kΩ

kbps

V

µs

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V ± 5%, TA= T

MIN

to T

MAX

. Typical values are at VCC= +3.3V, TA= +25°C, unless otherwise noted. See Note 2 for V+

and V- input voltage conditions.)

Note 2: The charge pump on the MAX3171/MAX3173 can supply V+ and V- to the MAX3172/MAX3174. The V+ and V- input levels

vary with the mode of chipset operation as follows:
V.35/V.28 modes: +5.55V ≤ V+ ≤ +6.50V, -6.50V ≤ V- ≤ -5.45V

Typical operation: V+ = +5.90V, V- = -5.80V
V.10/V.11 modes: +4.20V ≤ V+ ≤ +5.0V, -4.60V ≤ V- ≤ -3.80V

Typical operation: V+ = +4.60V, V- = -4.20V
The MAX3171/MAX3173 are guaranteed to provide these V+/V- supply levels.

V.28 TRANSMITTER

Output Voltage Swing V

Short-Circuit Current I

Output Slew Rate SR

Transmitter Propagation Delay t

Data Skew

V.28 RECEIVER

Input Threshold Low V
Input Threshold High V
Input Hysteresis V

Receiver Propagation Delay t

Data Skew

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

RL = 3kΩ, Figure 3 ±5.0 ±5.4

O

Open circuit, Figure 3 ±6.5
T4OUT = GND ±25 ±60 mA
RL = 3kΩ,

C

= 2500pF

L

measured from +3V
to -3V or -3V to +3V,
Figure 3

R

= 7kΩ , CL = 150pF measured from

L

+3V to -3V or -3V to +3V, Figure 3

PLH

-

|

Figure 4

PLH

­Figure 4

|

MAX3172CAI
MAX3174CAI

MAX3172EAI 3 30

MAX3172 5 10 15 µs
MAX3174 200 ns
MAX3172CAI 0.5 4
MAX3172EAI 0.5 5
MAX3174 100 ns

430

630

2.0 1.6 V

PHL

| t

PHL

| t

t

PLH

t

PLH

SC

, t

PHL

IL
IH

HYS

, t

PHL

V

V/µs

1µs

100 ns

1.1 0.8 V

0.5 V

µs

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(V

CC

= +3.3V (see Note 2 in Electrical Characteristics table), TA= +25°C, unless otherwise noted.)

V.10 60kbps TRANSMITTER

WAVEFORM (450Ω/100pF)

MAX3172-04

10µs/div

0

5V

0

5V

-5V

5V/div

T4OUT

5V/div

T4IN

100

102
101

104
103

106
105

107

109
108

110

-10 10 20 3004050607080

V.11/V.35 DIFFERENTIAL-MODE

IMPEDANCE vs. TEMPERATURE

MAX3172-05

TEMPERATURE (°C)

DIFFERENTIAL-MODE IMPEDANCE (Ω)

VCM = -7V

VCM = 0

VCM = +7V

100

103
102
101

105
104

109
108
107
106

110

-7 -5 -3 -1 1357

V.11/V.35 DIFFERENTIAL-MODE

IMPEDANCE vs. COMMON-MODE VOLTAGE

MAX3172-06

COMMON-MODE VOLTAGE (V)

DIFFERENTIAL-MODE IMPEDANCE (Ω)

V.28 SLEW RATE

vs. LOAD CAPACITANCE

24
22
20
18
16
14
12
10

SLEW RATE (V/µs)

8
6
4
2

0

+SLEW

-SLEW

500

0

1000 1500

LOAD CAPACITANCE (pF)

2000

RL = 3kΩ

2500

MAX3172-01

3000

V.10 RISE AND FALL TIMES

vs. LOAD CAPACITANCE

2.5

FALL TIME

2.0

1.5

RISE TIME

1.0

MAX3172-03

WAVEFORM (3kΩ/1000pF LOAD)

5V

0

5V

0

-5V

V.28 60kbps TRANSMITTER

10µs/div

MAX3172-02

T4IN
5V/div

T4OUT
5V/div

RISE AND FALL TIMES (µs)

0.5

0

RL = 450Ω

0 1000500 1500 2000 2500 3000

LOAD CAPACITANCE (pF)

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(V

CC

= +3.3V (see Note 2 in Electrical Characteristics table), TA= +25°C, unless otherwise noted.)

105.0

V.11/V.35 DIFFERENTIAL-MODE

IMPEDANCE vs. V+

V.11/V.35 DIFFERENTIAL-MODE

IMPEDANCE vs. V-

105.0

104.5

104.0

103.5

DIFFERENTIAL-MODE IMPEDANCE (Ω)

103.0

4.2 4.84.4 4.6 5.0 5.2 5.4
V+ (V)

V.35 COMMON-MODE IMPEDANCE

154

153

152

151

150

149

COMMON-MODE IMPEDANCE (Ω)

148

147

-10 10 200304050607080

vs. TEMPERATURE

VCM = 2.0V

VCM = 0

VCM = -2.0V

TEMPERATURE (°C)

MAX3172-07

MAX3172-09

104.5

104.0

103.5

DIFFERENTIAL-MODE IMPEDANCE (Ω)

103.0

-5.4 -4.4-4.6-5.0-5.2 -4.8 -4.2 -4.0 -3.8 -3.6
V- (V)

V.35 COMMON-MODE IMPEDANCE

vs. COMMON-MODE VOLTAGE

154

153

152

151

150

COMMON-MODE IMPEDANCE (Ω)

149

148

-2.0 -1.0-1.5 -0.5 0 0.5 1.0 1.5 2.0

COMMON-MODE VOLTAGE (V)

MAX3172-08

MAX3172-10

V.35 COMMON-MODE

IMPEDANCE vs. V+

165

160

155

150

145

COMMON-MODE IMPEDANCE (Ω)

140

135

5.5 5.95.7 6.1 6.3 6.5
V+ (V)

MAX3172-11

165

160

155

150

145

COMMON-MODE IMPEDANCE (Ω)

140

135

-6.6 -6.2 -6.0-6.4 -5.8 -5.6 -5.4

V.35 COMMON-MODE

IMPEDANCE vs. V-

V- (V)

MAX3172-12

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

_______________________________________________________________________________________ 7

Figure 1. V.11 or V.35 Differential Impedance Measurement

Figure 2. V.35 Common-Mode Impedance Measurement

Figure 3. V.10/V.28 Driver Test Circuit

Figure 4. V.10/V.28 Receiver Test Circuit

Test Circuits

A

R1
52Ω

OHMMETER

B

S1 ON

R3

127Ω

S2 OFF

R2
52Ω

VCM = ±7V OR ±2V

A

R1
52Ω

S1 ON

R3

OHMMETER

R2

VCM = ±2V

B

52Ω

127Ω

S2 ON

T

C

L

TR

R

L

15pF

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers

8 _______________________________________________________________________________________

Pin Description

PIN NAME FUNCTION

1M2Mode-Select Pin (see Tables 1 and 3 for detailed information)

2M1Mode-Select Pin (see Tables 1 and 3 for detailed information)

3M0Mode-Select Pin (see Tables 1 and 3 for detailed information)

4V

5 R5A Termination Network 5 Node A

6 R5B Termination Network 5 Node B

7 T4IN Transmitter CMOS Input

8 R4OUT Receiver CMOS Output

9,18, 22 GND Ground

10 R4B Termination Network 4 Node B

11 R4A Termination Network 4 Node A

12 R3C Termination Network 3 Node C

13 R3B Termination Network 3 Node B

14 R3A Termination Network 3 Node A

15 R1A Termination Network 1 Node A

16 R1B Termination Network 1 Node B

CC

+3.3V Supply Voltage (±5%). Bypass VCC to GND with a 0.1µF capacitor.

17 R1C Termination Network 1 Node C

19 R2C Termination Network 2 Node C

20 R2B Termination Network 2 Node B

21 R2A Termination Network 2 Node A

23 R4INA Inverting Receiver Input

24 V-

25 T4OUT Inverting Transmitter Output

26 V+

27 DCE/DTE

28 INVERT

Negative Supply (connect to V- pin of MAX3171/MAX3173). Bypass V- to GND with
a 0.1µF capacitor.

Positive Supply (connect to V+ pin of MAX3171/MAX3173). Bypass V+ to GND with
a 0.1µF capacitor.

DCE/DTE Mode-Select Pin. Logic level LOW selects DTE interface. See Tables 1
and 3 for detailed information.

Mode-Select Pin (inverts functionality of DCE/DTE input for T4/R4). See Tables 1 and
3 for detailed information.

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

_______________________________________________________________________________________ 9

Detailed Description

The MAX3172/MAX3174 contain five software-selectable
multiprotocol cable termination networks. Each network is
capable of terminating V.11 transceivers (RS-422, RS­530, RS-530A, RS-449, V.36, and X.21) with a 100Ω dif­ferential load, V.35 transceivers with a T-network load, or
V.28 (RS-232) and V.10 transceivers (RS-423) with an
open circuit load. The MAX3172/MAX3174, along with the
MAX3170 and MAX3171/MAX3173, form a complete
+3.3V software-selectable DTE or DCE interface port sup­porting V.11/RS-422, RS-530, RS-530A, V.36/RS-449,
V.35, V.28/RS-232, V.10/RS-423, and X.21 serial inter­faces.

The MAX3172/MAX3174 also contain a multiprotocol
transceiver that is software-selectable between V.10 and
V.28 operation modes. This transceiver is intended as the
handshake signal I/O in a DCE/DTE port application, and
is designed to use V+ and V- levels generated by the
MAX3171/MAX3173 charge pump. The MAX3172 fea­tures 10µs deglitching on the V.10/V.28 receiver input to
allow unterminated operation. The MAX3174 is used in
applications that do not require deglitching on the serial
handshake signals.

No-Cable Mode

The MAX3172/MAX3174 enter no-cable mode when the
mode-select inputs are all HIGH (M0 = M1 = M2 = 1). In
this mode, the driver, receiver, and bias circuitry are dis­abled, and the supply current drops to less than 200µA.

In no-cable mode, all five termination networks are
placed in the V.11 mode of operation (shorting pins R_A
and R_B with a 100Ω resistor). The receiver output enters
a high-impedance state in no-cable mode, allowing this
output line to be shared with other receivers (the receiver
output has an internal pullup resistor to pull the output
HIGH if not driven). Also, in no-cable mode, the transmit­ter output enters a high-impedance state so that this out­put can be shared with other devices.

Cable Termination

The MAX3172/MAX3174 software-selectable resistor net­works are intended for use with the MAX3170 clock/data
transceiver chip. The termination network is used for the
V.11, V.35, and V.28 transmitters. The MAX3172/
MAX3174 provide the advantage of not having to build
expensive termination networks from resistors and relays,
manually changing termination modules, or building ter­mination networks into custom cables.

Each termination network can be in one of three modes:
V.35, V.11, or high impedance (high-Z) as shown in
Figure 5 (see Table 2). For example, in V.35 mode, all five

Table 1. Termination Mode Selection

Table 2. Switch Configuration by Mode

MODE M2 M1 M0 DCE/DTE INVERT R1 R2 R3 R4 R5

V.10/RS-423 0 0 0 0 X Z Z Z Z Z
RS-530A 0 0 1 0 X Z Z V.11 V.11 V.11
RS-530 0 1 0 0 X Z Z V.11 V.11 V.11
X.21 0 1 1 0 X Z Z V.11 V.11 V.11
V.35 1 0 0 0 X V.35 V.35 V.35 V.35 V.35
RS-449/V.36 1 0 1 0 X Z Z V.11 V.11 V.11
V.28/RS-232 1 1 0 0 X Z Z Z Z Z
No Cable 1 1 1 0 X V.11 V.11 V.11 V.11 V.11
V.10/RS-423 0 0 0 1 X Z Z Z Z Z
RS-530A 0 0 1 1 X Z Z Z V.11 V.11
RS-530 0 1 0 1 X Z Z Z V.11 V.11
X.21 0 1 1 1 X Z Z Z V.11 V.11
V.35 1 0 0 1 X V.35 V.35 V.35 V.35 V.35
RS-449/V.36 1 0 1 1 X Z Z Z V.11 V.11
V.28/RS-232 1 1 0 1 X Z Z Z Z Z
No Cable 1 1 1 1 X V.11 V.11 V.11 V.11 V.11

MODE SW1 SW2

V.35 ON ON
V.11 ON OFF
V.28/V.10 (Z) OFF OFF

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers

10 ______________________________________________________________________________________

networks are configured to provide 100Ω differential
impedance and 150Ω common-mode impedance to ter­minate the MAX3170 V.35 transmitter outputs and receiv­er inputs.

Termination Mode Selection

The mode-select pins M0, M1, M2, and DCE/DTE control
the state of the five termination networks (Table 1). The
mode-select table of the MAX3172/MAX3174 is compati­ble with the MAX3170 mode-select table so that the M0,

M1, M2, and DCE/DTE pins can be connected to the cor­responding pins on the MAX3170. For example, M2 = 1,
M1 = 0, M0 = 0 corresponds to V.35 mode for both the
MAX3172/MAX3174 and the MAX3170 clock/data trans­ceiver chip.

R4/T4 Mode Selection

The MAX3172/MAX3174 include a transceiver for use in
applications requiring an extra serial handshake signal
(for example, local loopback). The transceiver can be

Table 3. R4/T4 Mode-Select Table

Not Used (Default V.11) 0 0 0 0 0 Z V.10
RS-530A 0 0 1 0 0 Z V.10
RS-530 0 1 0 0 0 Z V.10
X.21 0 1 1 0 0 Z V.10
V.35 1 0 0 0 0 Z V.28
RS-449/V.36 1 0 1 0 0 Z V.10
V.28/RS-232 1 1 0 0 0 Z V.28
No Cable 1 1 1 0 0 Z Z
Not Used (Default V.11) 0 0 0 1 0 V.10 Z
RS-530A 0 0 1 1 0 V.10 Z
RS-530 0 1 0 1 0 V.10 Z
X.21 0 1 1 1 0 V.10 Z
V.35 1 0 0 1 0 V.28 Z
RS-449/V.36 1 0 1 1 0 V.10 Z
V.28/RS-232 1 1 0 1 0 V.28 Z
No Cable 1 1 1 1 0 Z Z
Not Used (Default V.11) 0 0 0 0 1 V.10 Z
RS-530A 0 0 1 0 1 V.10 Z
RS-530 0 1 0 0 1 V.10 Z
X.21 0 1 1 0 1 V.10 Z
V.35 1 0 0 0 1 V.28 Z
RS-449/V.36 1 0 1 0 1 V.10 Z
V.28/RS-232 1 1 0 0 1 V.28 Z
No Cable 1 1 1 0 1 Z Z
Not Used (Default V.11) 0 0 0 1 1 Z V.10
RS-530A 0 0 1 1 1 Z V.10
RS-530 0 1 0 1 1 Z V.10
X.21 0 1 1 1 1 Z V.10
V.35 1 0 0 1 1 Z V.28
RS-449/V.36 1 0 1 1 1 Z V.10
V.28/RS-232 1 1 0 1 1 Z V.28
No Cable 1 1 1 1 1 Z Z

PROTOCOL M2 M1 M0 DCE/DTE INVERT T4 R4

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

______________________________________________________________________________________ 11

configured for V.10 or V.28 operation as a driver or
receiver (Table 3). This mode-selection table is compati­ble for use with the MAX3170 (clock/data transceiver)
and the MAX3171/MAX3173 (control transceiver). For
example, if X.21 mode is selected in DCE mode (M2 = 0,
M1 = 1, M0 = 1, and DCE/DTE = 1), the MAX3170,
MAX3171/MAX3173, and MAX3172/MAX3174 trans­ceivers will all be placed in X.21 DCE mode.

Fail-Safe

The MAX3172/MAX3174 guarantee a logic HIGH
receiver output when the receiver input is shorted to
GND or when it is connected to a terminated transmis­sion line with the driver disabled. The V.10 receiver

threshold is between +25mV and +250mV. If the V.10
receiver input voltage is less than +25mV, R4OUT is
logic HIGH. If the V.10 receiver input is greater than
+250mV, R4OUT is logic LOW.

The V.28 receiver threshold is between +0.8V and
+2.0V. If the V.28 receiver input voltage is less than
+0.8V, R4OUT is logic HIGH. If the receiver input is
greater than +2.0V, R4OUT is logic LOW. If the driving
transmitter is disabled or disconnected, the receiver’s
input voltage is pulled to zero by its internal termination.
With the receiver thresholds of the MAX3172/MAX3174,
this results in a logic HIGH.

Applications Information

Older multiprotocol cable termination implementations
have been constructed using expensive relays with dis­crete resistors, custom cables with built-in termination,
or complex circuit board configurations to route signals
to the correct termination. The MAX3172/MAX3174 pro­vide a simple solution to this termination problem. All
required termination configurations are software selec­table using four mode-control input pins (M2, M1, M0,
and DCE/DTE).

V.11 Termination

For high-speed data transmission, the V.11 specifica­tion recommends terminating the cable at the receiver

Figure 6. Typical V.11 Interface

A

B

S2 OFF

V.11 MODE V.35 MODE HIGH-Z MODE

A

C*

B

S2 ON

S1 OFF

A

B

S2 OFF

C*

C*

*NODE C IS PROVIDED IN NETWORKS 1,2,3.

R2
52Ω

R1
52Ω

S1 ON

R3

127Ω

R2
52Ω

R1
52Ω

S1 ON

R3

127Ω

R2
52Ω

R1
52Ω

R3

127Ω

Figure 5. MAX3172/MAX3174 Termination Network Configurations

BALANCED

INTERCONNECTING

GENERATOR

CABLE

TERMINATION

A

B
C

A′

B′
C′

CABLE

100Ω

MIN

LOAD

RECEIVER

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers

12 ______________________________________________________________________________________

with a minimum of a 100Ω resistor (Figure 6). This resis­tor, although not required, prevents reflections from
corrupting transmitted data.

In Figure 7, the MAX3172/MAX3174 are used to termi-
nate the V.11 receiver. Internal to the MAX3172/
MAX3174, S1 is closed and S2 is open to present a
104Ω typical differential resistance and high-Z com­mon-mode impedance. S3 opens to disable the
MAX3170’s internal V.28 termination.

The V.11 specification allows for signals with common­mode variations of ±7V with differential signal ampli­tudes from 2V to 6V. Also, data rates may be as high as

10Mbps. The MAX3172/MAX3174 maintain steady ter­mination impedance between 100Ω and 110Ω over
these conditions.

V.35 Termination

Figure 8 shows a standard V.35 interface. The genera-

tor and the load must both present a 100Ω ±1 0 Ω differ-
ential impedance and a 150Ω ±1 5 Ω common-mode
impedance (as shown by the resistive T-networks in

Figure 8). The V.35 driver generates a current output

(typically ±11mA) that develops an output voltage
between 440mV and 660mV across the load termina­tion networks.

Figure 8. Typical V.35 Interface

Figure 7. V.11 Termination and Internal Resistance Networks

A′

R1
52Ω

S1

R2
52Ω

B′

C′

MAX3172
MAX3174

R3

127Ω

S2

GENERATOR

A

A

B

BALANCED

INTERCONNECTING

CABLE

GND

R5

30kΩ
R8
5kΩ

S3

30kΩ

A′

R6

10kΩ

R7

10kΩ

R4

CABLE

TERMINATION

MAX3170

RECEIVER

LOAD

RECEIVER

50Ω

125Ω

50Ω

B

C

B′

C′

125Ω

50Ω

50Ω

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

______________________________________________________________________________________ 13

In Figure 9, the MAX3172/MAX3174 are used to imple-
ment 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 termina-

tion resistor, internal to the MAX3170, is disabled by
opening S3 to avoid interference with the T-network
impedance.

The V.35 specification allows for ±4V of ground differ­ence between the V.35 generator and V.35 load. The
V.35 data rates may be as high as 10Mbps. The
MAX3172/MAX3174 maintain correct terminal imped­ances over these conditions.

V.35 EMI Reduction

For applications where EMI reduction is especially
important, the MAX3172/MAX3174 termination net­works provide a pin for shunting common-mode driver
currents to GND (Figure 10). Mismatches between A
and B driver output propagation delays create a com­mon-mode disturbance on the cable. This common­mode energy can be shunted to GND by placing a
100pF capacitor (C1 to GND) from the center point of
the T-network termination (R1C, R2C, and R3C).

V.28 Termination

Most industry-standard V.28 receivers (including the
MAX3170) do not require external termination because
the receiver includes an internal 5kΩ termination resis­tor. When the MAX3172/MAX3174 are placed in V.28
mode, all five of the termination networks are placed in
a high-Z mode. In high-Z mode, the MAX3172/
MAX3174 termination networks will not interfere with the
MAX3170's internal 5kΩ termination.

Figure 9. V.35 Termination and Internal Resistance Networks

Figure 10. V.35 Driver

R3

127Ω

R2
52Ω

R1
52Ω

A

B

C(GND)

MAX3172
MAX3174

S1

S2

C1
100pF

DRIVER

R_C

A′

R1
52Ω

S1

R2
52Ω

B′

C′

MAX3172
MAX3174

R3

127Ω

S2

A

R5

30kΩ

R8
5kΩ

S3

B

GND

R4

30kΩ

10kΩ

10kΩ

R6

R7

MAX3170

RECEIVER

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers

14 ______________________________________________________________________________________

In Figure 11, the MAX3170 and MAX3172/MAX3174 are
placed in V.28 mode. Switches S1 and S2 are opened
on the MAX3172/MAX3174 to place the network in high­Z mode. Switch S3 is closed on the MAX3170 to enable
the 5kΩ terminating resistor.

V.28 Interface

The V.28 interface is an unbalanced single-ended inter­face (Figure 12). The V.28 driver generates a minimum
of ±5V across the load impedance between A' and C'.

The V.28 receiver specification calls for input trip points
at ±3V. To aid in rejecting system noise, the MAX3170
V.28 receiver has a typical hysteresis of 0.5V. Also, the
MAX3172/MAX3174 have more tightly specified input
trip points to guarantee fail-safe operation (see Fail-
Safe).

The MAX3172/MAX3174 V.28 receiver provides an
internal 5kΩ termination resistance.

V.10 Interface

The V.10 interface (Figure 12) is an unbalanced single­ended interface capable of driving a 450Ω load. The
V.10 driver generates a minimum voltage of ±4V
(V

ODO

) across A' and C' when unloaded and a mini-

mum voltage of ±0.9 ✕V

ODO

when loaded with 450Ω.
The V.10 receiver input trip threshold is defined
between +300mV and -300mV with input impedance
characteristics shown in Figure 13.

The MAX3172/MAX3174 V.10 mode receiver has a
threshold between +25mV and +250mV to ensure that
the receiver has proper fail-safe operation (see Fail-
Safe). To aid in rejecting system noise, the MAX3172/
MAX3174 V.10 receiver has a typical hysteresis of
15mV. Switch S3 in Figure 14 is open in V.10 mode to
disable the 5kΩ V.28 termination at the receiver input.

Receiver Glitch Rejection

To allow operation in an unterminated or otherwise
noisy system, the MAX3172 features 10µs of receiver
input glitch rejection. The glitch-rejection circuitry
blocks the reception of high-frequency noise with a bit
period less than 5µs while receiving low-frequency sig­nals with a bit period greater than 15µs, allowing glitch­free operation in unterminated systems at up to 64kbps.

Figure 12. Typical V.28 and V.10 Interface

Figure 11. V.28 Termination and Internal Resistance Networks

Figure 13. V.10 Receiver Input Impedance

A′

R1

MAX3172

52Ω

MAX3174

S1

R2
52Ω

B′

C′

GENERATOR

-10V

-3.25mA

UNBALANCED

INTERCONNECTING

CABLE

A

C

I

Z

-3V

TERMINATION

A′

C′

S2

+3V

CABLE

R3

127Ω

LOAD

RECEIVER

3.25mA

+10V

A

R5

30kΩ

R8
5kΩ

S3

B

GND

R4

30kΩ

10kΩ

10kΩ

R6

R7

MAX3170

RECEIVER

V

Z

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

______________________________________________________________________________________ 15

The MAX3174 does not have this glitch rejection and
can be operated at frequencies up to 240kbps if prop­erly terminated.

DCE vs. DTE Operation

Figure 15 illustrates a DCE or DTE controller-selectable
interface. The DCE/DTE input switches the MAX3172/
MAX3174s’ mode of operation. Logic high selects DCE,
which enables driver 4 on the MAX3172/MAX3174
(INVERT = 0), driver 3 on the MAX3171/MAX3173, and
driver 3 on the MAX3170. A logic low selects DTE,
which enables receiver 4 on the MAX3172/MAX3174
(INVERT = 0), receiver 1 on the MAX3171/MAX3173,
and receiver 1 on the MAX3170.

This application requires only one DB-25 connector.
See Figure 15 for complete signal routing in DCE and
DTE modes. For example, driver 4 routes the LL(DCE)
signal to pin 18 in DCE mode, while in DTE mode,
receiver 4 routes pin 18 to the LL(DTE) signal.

Complete Multiprotocol X.21 Interface

A complete DTE-to-DCE interface operating in X.21
mode is shown in Figure 16. The MAX3172/MAX3174 ter­minate the V.11 clock and data signals, and its transceiv­er carries the local loopback (LL) signal. The MAX3170
carries the clock and data signals, and the
MAX3171/MAX3173 carry the control signals. The control
signals generally do not require external termination.

Compliance Testing

A European Standard EN45001 test report is available
for the MAX3170–MAX3174 chipset. A copy of the test
report is available from Maxim upon request.

R6
10kΩ

R8
5kΩ

A′

C′

A

GND

R5

30kΩ

R7
10kΩ

R4

30kΩ

MAX3172
MAX3174

S3

RECEIVER

Figure 14. V.10 Internal Resistance Networks

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers

16 ______________________________________________________________________________________

Figure 15. Multiprotocol DCE/DTE Port

MAX3171
MAX3173

CTS(DTE)
RTS(DCE)

DSR(DTE)
DTR(DCE)

R2R3

R1

DCD(DTE)

DCD(DCE)

D3

DTR(DTE)

DSR(DCE)

D2

RTS(DTE)

CTS(DCE)

D1

13 5 10 8 22 6 23 20 19 4 1 7 18 16 3 9 17 12 15 11 24 14 2

DTE

CTS B

CTS A

DSR B

DSR A

DCE

RTS B

RTS A

DTR B

DTR A

DCD B

DCD B

DCD A

DCD A

DTR B

DSR B

DTR A

DSR A

RTS B

CTS B

RTS A

CTS A

M1M2M0

DCE/DTE

SHIELD

RXD(DTE)
TXD(DCE)

LL(DTE)
LL(DCE)

MAX3172
MAX3174

R4

D4

DCE/DTE

M2M1M0

SG

LL A

DB-25 CONNECTOR

LL A

RXC(DTE)

SCTE(DCE)

RXD B

RXD A

TXD B

TXD A

R2R3

RXC B

SCTE B

R1

RXC A

SCTE A

TXC(DTE)
TXC(DCE)

D3

TXC B

TXC B

SCTE(DTE)

RXC(DCE)

TXC A

SCTE B

TXC A

RXC B

TXD(DTE)
RXD(DCE)

D1D2

TXD B

SCTE A

RXC A

RXD B

TXD A

RXD A

MAX3170

M1M2M0

M1M2M0

DCE/DTE

DCE/DTE

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

______________________________________________________________________________________ 17

Figure 16. DCE-TO-DTE X.21 Interface

SERIAL

CONTROLLER

SCTE

TXD

TXC

RXC

RXD

RTS

DTE

MAX3170

D1

D2

D3

R1

R2

R3

LL

MAX3171
MAX3173

D1

MAX3172
MAX3174

103Ω

103Ω

103Ω

D4

R4

TXD

SCTE

TXC

RXC

RXD

LL

RTS

MAX3174

103Ω

103Ω

R4

D4

DCE

MAX3170MAX3172

MAX3171
MAX3173

SERIAL

CONTROLLER

R3

R2

R1

D3

D2

D1

R3

TXD

SCTE

TXC

RXC

RXD

LL

RTS

DTR

DCD

DSR

CTS

D2

D3

R1

R2

R3

DTR

DCD

DSR

CTS

R2

R1

D3

D2

D1

DTR

DCD

DSR

CTS

MAX3172/MAX3174

+3.3V Multiprotocol Software-Selectable
Cable Terminators and Transceivers

18 ______________________________________________________________________________________

Pin Configuration

28

27

26

25

24

23

22

21

20

19

18

17

16

15

1

2

3

4

5

6

7

8

9

10

11

12

13

14

INVERT

DCE/DTE

V+

T4OUT

V-

R4INA

R1A

GND

R2A

R2B

R2C

GND

R1C

R1B

R3A

R3B

R3C

R4A

R4B

GND

R4OUT

T4IN

R5B

R5A

V

CC

M0

M1

M2

28 SSOP

TOP VIEW

MAX3172
MAX3174

Chip Information

TRANSISTOR COUNT: 2506

+3.3V Multiprotocol Software-Selectable

Cable Terminators and Transceivers

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 ____________________ 19

© 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

MAX3172/MAX3174

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages

.)

e

D

12

INCHES

DIM

MIN

A

0.068

A1

0.002

B

0.010

C

HE

N

A

B

A1

D

E

e

H

L

0.004

SEE VARIATIONS

0.205

0.0256 BSC

0.301

0.025

0∞

L

MAX

0.078

0.008

0.015

0.008

0.212

0.311

0.037

8∞

MILLIMETERS

MAX

MIN

1.73 1.99

0.21

0.05

0.38

0.25

0.20

0.09

5.38

5.20

0.65 BSC

7.90

7.65

0.63

0.95

0∞

8∞

INCHES

MIN

D

0.239

D

0.239

D

0.278

D

0.317

0.397

D

MAX

0.249

0.249

0.289

0.328

0.407

MILLIMETERS

MAX

MIN

6.07

6.33

6.07

6.33

7.07

7.33

8.07

8.33

10.07

10.33

N

14L
16L

20L

24L

28L

C

SSOP.EPS

NOTES:

1. D&E DO NOT INCLUDE MOLD FLASH.

2. MOLD FLASH OR PROTRUSIONS NOT TO EXCEED .15 MM (.006").

3. CONTROLLING DIMENSION: MILLIMETERS.

4. MEETS JEDEC MO150.

5. LEADS TO BE COPLANAR WITHIN 0.10 MM.

PROPRIETARY INFORMATION

TITLE:

PACKAGE OUTLINE, SSOP, 5.3 MM

21-0056

REV.DOCUMENT CONTROL NO.APPROVAL

1

C

1