Datasheet MAX3170CAI Datasheet (Maxim)

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.

________________________Applications

Data Networking PCI Cards

CSU and DSU Telecommunications

Data Routers

Features

♦ Industry’s First +3.3V Single-Supply Transceiver

♦ 3V/5V Logic-Compatible I/O

♦ Certified TBR-1 and TBR-2 Compliant (NET1 and

NET2)—Pending Completion

♦ Supports V.28 (RS-232), V.11 (RS-449/V.36,

EIA530, EIA530-A, X.21), and V.35 Protocols

♦ Software-Selectable DTE/DCE

♦ Complete DTE/DCE Port with MAX3171/MAX3173

and MAX3172/MAX3174

♦ True Fail-Safe Receiver Operation

♦ Available in Small 28-Pin SSOP Package

♦ 10Mbps Operation (V.11/V.35)

♦ Requires Only Four Tiny Surface-Mount

Capacitors

♦ All Transmitter Outputs Are Fault Protected to

±15V to Survive Cable Miswiring

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software-

Selectable Clock/Data Transceiver

________________________________________________________________ Maxim Integrated Products 1

19-1703; Rev 0; 4/00

For free samples and the latest literature, visit www.maxim-ic.com or phone [phone].
For small orders, phone [phone].

Ordering Information

Pin Configuration appears at end of data sheet.

Typical Operating Circuit

PART TEMP. RANGE PIN-PACKAGE

MAX3170CAI 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 1215 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

R4

SG

DB-25 CONNECTOR

D4

RXD RXC TXDTXC SCTE

R1

R2R3

LL A

RXD A

RXD B

RXC B

RXC A

D3

TXC B

TXC A

SCTE B

SCTE A

D1D2

TXD B

MAX3170

TXD A

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software­Selectable Clock/Data Transceiver

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3.3V ±5%, C1 = C2 = 1µF, C3 = C4 = 3.3µF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C

and V

CC

= +3.3V.)

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, T_IN ...............................-0.3V to +6V

Logic Output Voltages

R_OUT...................................................-0.3V to (V

CC

+ 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 (T

A

= +70°C)

28-Pin SSOP (derate 11.1mW/°C above +70°C) ........889mW

Operating Temperature Range

MAX3170CAI .....................................................0°C to +70°C

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

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

PARAMETER

DC CHARACTERISTICS

Supply Current (DCE Mode)
(Digital Inputs = GND or V
(All Outputs Static)

Internal Power Dissipation
(DCE Mode)

V+ Output Voltage (DCE Mode)
(Full Load)

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

CC

)

SYMBOL

I

CC

P

D

V+

V-

V

IH

V

IL

I

IN

I

IH

I

IL

V.11 mode

V.11 mode with no load

V.35 mode

V.35 mode with no load

V.28 mode

V.28 mode with no load

No-cable mode

V.11 mode, full load

V.35 mode, full load

V.28 mode, full load

V.11 mode

V.35 mode

V.28 mode

No-cable mode

V.11 mode

V.35 mode

V.28 mode

No-cable mode

Delay until V+ and V- specifications met

T_IN
M0, M1, M2, DCE/DTE = V

M0, M1, M2, DCE/DTE = GND

CONDITIONS

MIN TYP MAX UNITS

190

3

160

20
10
4

0.8

410

510

15

4

4.25

5.55

5

-4.25

1

2.0

CC

30

50

250

7

210

40

20

7

2

-4.1

-3.7

-5.45

0.8

±1

±1

100

mA

mW

V

V

ms

V

V

µA

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software-

Selectable Clock/Data Transceiver

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V ±5%, C1 = C2 = 1µF, C3 = C4 = 3.3µF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C

and V

CC

= +3.3V.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
LOGIC OUTPUTS (R_OUT)
Output High Voltage V
Output Low Voltage V
Rise or Fall Time t
Output Leakage Current

(Receiver Output Tristated)

OH

OL

, t

r

I
I
10% to 90% 15 ns

f

= 1.0mA VCC - 1.0 V

SOURCE

= 1.6mA 0.4 V

SINK

R_OUT = GND 30 50 100

R_OUT = V

CC

±1

µA

TRANSMITTER OUTPUTS

Output Leakage Current I

Data Rate

Z

-0.25V < V

no-cable mode

V.11/ V.35 mode 10 Mbps

V.28 mode 240 kbps

< +0.25V power-off or

OUT

±100 µA

RECEIVER INPUTS

Receiver Input Resistance R

Data Rate

-10V < V

IN

(V.11/V.35/no-cable mode)

-15V < V
V.11/ V.35 mode 10 Mbps

V.28 mode 240 kbps

< +10V, VA or VB grounded

A,B

< +15V (V.28 mode) 3 5 7

A

20 40

kΩ

V.11 TRANSMITTER
Unloaded Differential Output

Voltage

V

ODO

R = 1.95kΩ, Figure 1 4.0 6.0 V

Loaded Differential Output

Voltage

C hang e i n M ag ni tud e of O utp ut
C om m on- M od e O utp ut V ol tag e V
C hang e i n M ag ni tud e of O utp ut

C om m on- M od e V ol tag e

Short-Circuit Current I
Rise or Fall Time t
Transmitter Input to Output t
Data Skew |t

PHL

PHL

Output-to-Output Skew t
Channel-to-Channel Output

V

ODL

∆V

OD

OC

∆V

OC

SC

, t

r

, t

- t

SKEW

R = 50Ω, Figure 1

R = 50Ω, Figure 1 0.2 V
R = 50Ω, Figure 1 3.0 V

R = 50Ω, Figure 1 0.2 V

V

= GND 60 150 mA

OUT

10% to 90%, Figure 2 10 25 ns

f

Figure 2 50 80 ns

PLH

| Figure 2 2 10 ns

PLH

Figure 2 2 ns
2 ns

2.0

0.5 x V

OD O

V

V.11 RECEIVER
Differential Threshold Voltage V
Input Hysteresis ∆V
Receiver Input to Output t
Data Skew |t

PHL

PHL

TH

TH

, t

- t

-7V < V

CM

-7V < V

CM

PLH VCM

PLH

= 0, Figure 2 60 120 ns

| VCM = 0, Figure 2

< +7V -200 -100 -25 mV
< +7V 15 mV

5 16

ns

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software­Selectable Clock/Data Transceiver

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V ±5%, C1 = C2 = 1µF, C3 = C4 = 3.3µF, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C

and V

CC

= +3.3V.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V.35 TRANSMITTER
Differential Output Voltage -4V < V
Output High Current I
Output Low Current I
Rise or Fall Time t
Transmitter Input to Output t
Data Skew |t

PHL

PHL

OH

OL

, t

r

, t

- t

f

PLH

PLH

| Figure 3 5 10 ns

CM

V

= 0 9 11 13 mA

A, B

V

= 0 -13 -11 -9 mA

A, B

10% to 90%, Figure 3 10 ns
Figure 3 50 80 ns

Output-to-Output Skew Figure 3 2 ns
C hannel- to-C hannel Output Skew 2 ns
V.35 RECEIVER
Differential Input Voltage V
Input Hysteresis ∆V
Receiver Input to Output t
Data Skew

|t

PHL

PHL

TH

TH

, t

- t

-4V < V

-4V < V

PLH VCM

V

|

PLH

CM

CM

CM

= 0 70 120 ns
= 0 5 16 ns

V.28 TRANSMITTER

Output Voltage Swing V

Short-Circuit Current I

SC

Output Slew Rate SR

Transmitter Input to Output t
Data Skew

|t

PHL

PHL

- t

O

, t

All transmitters loaded with R
No load ±6.5

±25 ±60 mA
R

= 3kΩ, CL = 2500pF, measured from

L

+3V to -3V or -3V to +3V, Figure 4

R

= 7kΩ, CL = 150pF, measured from

L

+3V to -3V or -3V to +3V, Figure 4

Figure 4 1 µs

PLH

Figure 4 100 ns

|

PLH

V.28 RECEIVER
Input Threshold Low V
Input Threshold High V
Input Hysteresis V
Data Skew |t

PHL

IL

IH

HYS

- t

Figure 5 0.8 1.1 V
Figure 5 1.6 2.0 V

| Figure 5 100 ns

PLH

< +4V, Figure 3 0.44 0.55 0.66 V

< +4V, Figure 3 -200 -100 -25 mV
< +4V, Figure 3 15 mV

= 3kΩ

L

±5.0 ±5.4

4 30

6 30

0.5 V

V

V/µs

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software-

Selectable Clock/Data Transceiver

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(VCC= +3.3V, C1 = C2 = 1.0µF, C3 = C4 = 3.3µF, TA= +25°C, unless otherwise noted.)

V.11 SUPPLY CURRENT

vs. DATA RATE

250

DCE MODE, R = 50Ω
ALL TRANSMITTERS OPERATING
AT SPECIFIED RATE

200

150

100

V.11 SUPPLY CURRENT (mA)

50

0

0.1 101 100 1000 10,000
DATA RATE (kbps)

V.11 DRIVER DIFFERENTIAL OUTPUT

VOLTAGE vs. TEMPERATURE

4

DCE MODE, R = 50Ω

3

2

1

0

-1

-2

-3

DRIVER DIFFERENTIAL OUTPUT VOLTAGE (V)

-4

-40 0-20 20 40 60 80

TEMPERATURE (°C)

V

OH

V

OL

100

MAX3170-01

80

60

40

V.28 SUPPLY CURRENT (mA)

20

0

8
7
6

MAX3170-04

5
4
3
2
1
0

-1

-2

-3

OUTPUT VOLTAGE (V)

-4

-5

-6

-7

-8

V.28 SUPPLY CURRENT

vs. DATA RATE

DCE MODE, ALL TRANSMITTERS
OPERATING AT THE SPECIFIED DATA RATE

= 3kΩ, CL = 2000pF

R

L

0 10050 150 200 250

DATA RATE (kbps)

V.28 OUTPUT VOLTAGE

vs. TEMPERATURE

DCE MODE, R = 3kΩ

-40 0-20 20 40 60 80
TEMPERATURE (°C)

VOUT+

VOUT-

200

DCE MODE, VCM = 0

MAX3170-02

ALL TRANSMITTERS OPERATING
AT SPECIFIED RATE

150

100

50

V.35 SUPPLY CURRENT (mA)

0

0.1 101 100 1000

V.35 DIFFERENTIAL OUTPUT VOLTAGE

0.66

MAX3170-05

DCE MODE, VCM = 0

0.44

0.22

0

-0.22

-0.44

DIFFERENTIAL OUTPUT VOLTAGE (V)

-0.66

-40 20 40-20 0 60 80

V.35 SUPPLY CURRENT

vs. DATA RATE

DATA RATE (kbps)

vs. TEMPERATURE

V

OH

V

OL

TEMPERATURE (°C)

MAX3170-03

10,000

MAX3170-06

V.35 DIFFERENTIAL OUTPUT VOLTAGE

vs. COMMON-MODE VOLTAGE

570

560

V

550

540

530

DIFFERENTIAL OUTPUT VOLTAGE (V)

520

-4 -2 -1-3 01234

OH

VCM (V)

V.11/V.35 RECEIVER INPUT CURRENT

300

DCE MODE

MAX3170-07

200

100

0

-100

RECEIVER INPUT CURRENT (µA)

-200

-300

-10 -2-4-8-6 0246810

vs. INPUT VOLTAGE

INPUT VOLTAGE (V)

2.5
DCE MODE

2.0

MAX3170-08

1.5

1.0

0.5

0

-0.5

-1.0

RECEIVER INPUT CURRENT (mA)

-1.5

-2.0

-2.5

-10 -6 -4 -2-8 024 8610

V.28 RECEIVER INPUT CURRENT

vs. INPUT VOLTAGE

MAX3170-09

INPUT VOLTAGE (V)

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software­Selectable Clock/Data Transceiver

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VCC= +3.3V, C1 = C2 = 1.0µF, C3 = C4 = 3.3µF, TA= +25°C, unless otherwise noted.)

V.11 LOOPBACK SCOPE PHOTO

MAX3170-10

50ns/div

TIN

ROUT

TOUT/RIN

2V/div

V.28 LOOPBACK SCOPE PHOTO

MAX3170-11

1µs/div

TIN

ROUT

TOUT/RIN

2V/div5V/div2V/div

V.35 LOOPBACK SCOPE PHOTO

MAX3170-12

50ns/div

TIN

ROUT

TOUT/RIN

2V/div

400mV/div2V/div

16

14

12

10

8

6

SLEW RATE (V/µs)

4

RL = 3kΩ

2

1 TRANSMITTER SWITCHING AT 250kbps;
OTHER TRANSMITTERS SWITCHING AT 15kbps

0

0 1000 2000 3000 4000

V.28 SLEW RATE

vs. LOAD CAPACITANCE

+SLEW

-SLEW

LOAD CAPACITANCE (pF)

V.35 TRANSMITTER PROPAGATION

60

50

40

30

20

PROPAGATION DELAY (ns)

10

0

-40 20 40-20 0 60 80

MAX3170-13

PROPAGATION DELAY (ns)

5000

DELAY vs. TEMPERATURE

t

PLH

t

PHL

TEMPERATURE (°C)

V.11 TRANSMITTER PROPAGATION

DELAY vs. TEMPERATURE

60

t

PLH

50

40

t

30

20

10

0

-40 20 40-20 0 60 80

PHL

TEMPERATURE (°C)

MAX3170-16

PROPAGATION DELAY (ns)

V.11 RECEIVER PROPAGATION DELAY

vs. TEMPERATURE

80

MAX3170-14

70

60

50

40

30

PROPAGATION DELAY (ns)

20

10

0

-40 0-20 20 40 60 80

t

V.35 RECEIVER PROPAGATION

DELAY vs. TEMPERATURE

80

70

60

50

40

30

20

10

0

-40 0-20 20 40 60 80

t

PLH

t

PHL

TEMPERATURE (°C)

PLH

t

PHL

TEMPERATURE (°C)

MAX3170-17

MAX3170-15

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software-

Selectable Clock/Data Transceiver

_______________________________________________________________________________________ 7

Figure 1. V.11 DC Test Circuit

Figure 2. V.11 AC Test Circuit

Figure 3. V.35 Transmitter/Receiver Test Circuit

Figure 4. V.28 Driver Test Circuit

Figure 5. V.28 Receiver Test Circuit

Test Circuits

V

OD

R

100Ω

V

125Ω

OC

50Ω

V

CM

125Ω

50Ω

R

50Ω

50Ω

100pF

50pF

100pF

50pF

C

L

R

L

50pF

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software­Selectable Clock/Data Transceiver

8 _______________________________________________________________________________________

Pin Description

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.

PIN NAME FUNCTION

1V+

2 C2+

3 C2-

4V-

5, 6, 7 T_IN Transmitter CMOS Inputs (T1IN, T2IN, T3IN)

8, 9, 10 R_OUT Receiver CMOS Outputs (R1OUT, R2OUT, R3OUT)

11, 12, 13 M_

14 DCE/DTE

15, 18 R_INB Noninverting Receiver Inputs (R3INB, R2INB)

16, 17 R_INA Inverting Receiver Inputs (R3INA, R2INA)

19 T3OUTB/R1INB Noninverting Transmitter Output/Noninverting Receiver Input

20 T3OUTA/R1INA Inverting Transmitter Output/Inverting Receiver Input

21, 23 T_OUTB Noninverting Transmitter Outputs (T2OUTB, T1OUTB)

Positive Supply Generated by the Charge Pump. Bypass V+ to ground with a 3.3µF ceramic
capacitor.

Positive Terminal of the Inverting Charge-Pump Capacitor. Connect C2+ to C2- with a 1µF
ceramic capacitor.

Negative Terminal of the Inverting Charge-Pump Capacitor. Connect C2+ to C2- with a 1µF
ceramic capacitor.

Negative Supply Generated by the Charge Pump. Bypass V- to ground with a 3.3µF ceramic
capacitor.

Mode Select Pins (M0, M1, M2). Internally pulled up to V
information.

DCE/DTE Mode Select Pin. Logic level high selects DCE interface; logic level low selects
DTE interface. Internally pulled up to V

CC

.

. See Table 1 for detailed

CC

22, 24 T_OUTA Inverting Transmitter Outputs (T2OUTA, T1OUTA)

25 C1-

26 GND Ground

27 V

28 C1+ Positive Terminal of the Voltage-Doubler Charge-Pump Capacitor. Connect C1+ to C1- with a

CC

Negative Terminal of the Voltage-Doubler Charge-Pump Capacitor. Connect C1+ to C1- with
a 1µF ceramic capacitor.

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

1µF ceramic capacitor.

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 VCCto 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.

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

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.

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

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software-

Selectable Clock/Data Transceiver

_______________________________________________________________________________________ 9

Table 1. Mode Selection

Z = High impedance

PROTOCOL

V.11 0 0 0 0 V.11 V.11 Z V.11 V.11 V.11

RS-530A 0 0 1 0 V.11 V.11 Z V.11 V.11 V.11

RS-530 0 1 0 0 V.11 V.11 Z V.11 V.11 V.11

X.21 0 1 1 0 V.11 V.11 Z V.11 V.11 V.11

V.35 1 0 0 0 V.35 V.35 Z V.35 V.35 V.35

RS-449/V.36 1 0 1 0 V.11 V.11 Z V.11 V.11 V.11

V.28/RS-232 1 1 0 0 V.28 V.28 Z V.28 V.28 V.28

No cable 1 1 1 0 ZZZZZZ

V.11 0 0 0 1 V.11 V.11 V.11 Z V.11 V.11

RS-530A 0 0 1 1 V.11 V.11 V.11 Z V.11 V.11

RS-530 0 1 0 1 V.11 V.11 V.11 Z V.11 V.11

X.21 0 1 1 1 V.11 V.11 V.11 Z V.11 V.11

V.35 1 0 0 1 V.35 V.35 V.35 Z V.35 V.35

RS-449/V.36 1 0 1 1 V.11 V.11 V.11 Z V.11 V.11

V.28/RS-232 1 1 0 1 V.28 V.28 V.28 Z V.28 V.28

No cable 1 1 1 1 ZZZZZZ

M2 M1 M0 DCE/DTE T1 T2 T3 R1 R2 R3

LOGIC INPUTS TRANSMITTERS RECEIVERS

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.

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 1µF, while the reservoir capacitors (C3, C4)
and bypass capacitor (C5) should have a minimum
value of 3.3µF (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.

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.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 100Ω
(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 100Ω 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 100Ω minimum differential resistance. The
MAX3170’s internal V.28 termination is disabled by
opening S3.

V.35 Interface

Figure 11 shows a fully balanced differential standard
V.35 interface. The generator and the load must both
present a 100Ω ±10Ω differential impedance and a
150Ω ±15Ω 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.

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software­Selectable Clock/Data Transceiver

10 ______________________________________________________________________________________

Figure 6. Charge-Pump Connections

C3

3.3µF
C2

1µF

C4

3.3µF

MAX3170

1

V+

2

C2+

3

C2-

4

V-

28

C1+

27

V

CC

GND

C1-

C5

26

3.3µF

25

C1
1µF

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software-

Selectable Clock/Data Transceiver

______________________________________________________________________________________ 11

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 5kΩ V.28 termination is enabled by
closing S3.

MAX3171
MAX3173

CTS(DTE)
RTS(DCE)

DSR(DTE)
DTR(DCE)

R1

R2R3

13 5 10 8 22 6 23 20 19 4 1 7 18 21 25 16 3 9 17 1215 11 24 14 2

DTE

CTS B

CTS A

DSR B

DSR A

DCE

RTS B

RTS A

DTR B

DTR A

DCD(DTE)
DCD(DCE)

D3

DCD B

DCD B

DTR(DTE)
DSR(DCE)

D2

DTR B

DCD A

DSR B

DCD A

RTS(DTE)

CTS(DCE)

D1

RTS B

DTR A

CTS B

DSR A

RTS A

CTS A

M1M2M0

V

CC

DCE/DTE

SHIELD

MAX3172
MAX3174

M1M0

SG

DB-25 CONNECTOR

R4

D4

DCE/DTE

M2M1M0

DCE/DTE

RXD(DTE)
TXD(DCE)

RXD B

TXD B

RXC(DTE)

SCTE(DCE)

R2R3

RXD A

RXC B

TXD A

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

DCE/DTE

CABLE WIRING FOR

MODE SELECTION

MODE

V.35
RS-449, V.36
RS-232
NO CABLE N.C. N.C.

PIN 18

PIN 7
N.C.
PIN 7

PIN 21

PIN 7
PIN 7
N.C.

CABLE WIRING FOR

DCE/DTE SELECTION

MODE

DTE
DCE

PIN 25

PIN 7
N.C.

Figure 11. Typical V.35 Interface

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software­Selectable Clock/Data Transceiver

12 ______________________________________________________________________________________

Figure 9. Receiver Input Impedance Curve

Figure 8. Typical V.11 Interface

Figure 10. V.11 Termination and Internal Resistance Networks

I

Z

GENERATOR

A

B

C

BALANCED

INTERCONNECTING

CABLE

CABLE

TERMINATION

A′

100Ω

MIN

B′

C′

LOAD

RECEIVER

-10V

-3.25mA

-3V

+3V

3.25mA

+10V

V

Z

A′

R1

51.5Ω

S1

R2

51.5Ω

B′

C′

MAX3172
MAX3174

R3

124Ω

S2

GENERATOR

A

BALANCED

INTERCONNECTING

A

B

CABLE

S3

GND

R5

30k
R8
5k

30k

R6

10k

R7

10k

R4

CABLE

A′

TERMINATION

MAX3170

RECEIVER

LOAD

RECEIVER

50Ω

50Ω

125Ω

125Ω

B

C

B′

C′

50Ω

50Ω

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software-

Selectable Clock/Data Transceiver

______________________________________________________________________________________ 13

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.

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’sR1 routes pins 12 and 15 to
TXC (DTE).

Complete Multiprotocol X.21 Interface

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.

Figure 12. V.35 Termination and Internal Resistance Networks

Figure 13. Typical V.28 Interface

A′

R1

51.5Ω

MAX3172
MAX3174

A

R5

30k

R8
5k

10k

R6

MAX3170

RECEIVER

S1

S2

R2

51.5Ω

B′

C′

UNBALANCED

INTERCONNECTING

GENERATOR

CABLE

A

C

C′

124Ω

CABLE

TERMINATION

A′

R3

B

LOAD

RECEIVER

S3

R7

10k

R4

30k

GND

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software­Selectable Clock/Data Transceiver

14 ______________________________________________________________________________________

Figure 15. Multiprotocol DCE/DTE Port

Figure 14. V.28 Termination and Internal Resistance Networks

A′

R1

51.5Ω

S1

R2

51.5Ω

B′

C′

MAX3172
MAX3174

R3

124Ω

S2

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

M1M2M0

DCE/DTE

A

RXC(DTE)

SCTE(DCE)

R2R3

MAX3170

RECEIVER

R1

TXC(DTE)
TXC(DCE)

D3

SCTE(DTE)

RXC(DCE)

TXD(DTE)
RXD(DCE)

D1D2

MAX3170

M1M2M0

DCE/DTE

R5

MAX3172
MAX3174

R4

D4

30k

30k

R6

10k

R7

10k

R4

RXD(DTE)
TXD(DCE)

LL(DTE)
LL(DCE)

R8

5k

S3

B

GND

DCE/DTE

M2M1M0

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

SG

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

SHIELD

LL A

LL A

DB-25 CONNECTOR

RXD B

TXD B

RXD A

TXD A

RXC B

SCTE B

RXC A

SCTE A

TXC B

TXC B

TXC A

TXC A

SCTE B

SCTE A

RXC B

RXC A

TXD B

RXD B

M1M2M0

DCE/DTE

TXD A

RXD A

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software-

Selectable Clock/Data Transceiver

______________________________________________________________________________________ 15

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

SERIAL

CONTROLLER

TXD

SCTE

TXC

RXC

RXD

DTR

RTS

DTE

MAX3170

D1

D2

D3

R1

R2

R3

LL

MAX3171
MAX3173

D1

D2

MAX3172
MAX3174

103Ω

103Ω

103Ω

D4

R4

TXD

SCTE

TXC

RXC

RXD

LL

RTS

DTR

MAX3174

103Ω

103Ω

R4

D4

DCE

MAX3170MAX3172

MAX3171
MAX3173

SERIAL

CONTROLLER

R3

R2

R1

D3

D2

D1

R3

R2

TXD

SCTE

TXC

RXC

RXD

LL

RTS

DTR

DCD

DSR

CTS

D3

R1

R2

R3

DCD

DSR

CTS

R1

D3

D2

D1

DCD

DSR

CTS

MAX3170

+3.3V, Multiprotocol, 3 Tx/3 Rx, Software­Selectable Clock/Data Transceiver

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

© 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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

© 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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

© 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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

© 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

Package Information

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

C1+

V

CC

GND

C1-

T1OUTA

T1OUTB

R3INB

T2OUTA

T2OUTB

T3OUTA/R1INA

T3OUTB/R1INB

R2INB

R2INA

R3INA

DCE/DTE

M2

M1

M0

R3OUT

R2OUT

R1OUT

T3IN

T2IN

T1IN

V-

C2-

C2+

V+

28 SSOP

TOP VIEW

MAX3170

Chip Information

TRANSISTOR COUNT: 4058

SSOP.EPS