MAXIM MAX3160, MAX3161, MAX3162 User Manual

General Description

The MAX3160/MAX3161/MAX3162 are programmable
RS-232/RS-485/422 multiprotocol transceivers. The
MAX3160/MAX3161 are pin programmable as a 2TX/2RX
RS-232 interface or a single RS-485/422 transceiver. The
MAX3162 is configured as a 2TX/2RX RS-232 interface
and a single RS-485/422 transceiver simultaneously.

All devices incorporate a proprietary low-dropout trans­mitter output stage and an on-board dual charge pump
to allow RS-232 and RS-485/422 compliant perfor­mance from a +3V to +5.5V supply. The receivers
feature true fail-safe circuitry that guarantees a logic­high receiver output when the receiver inputs are open
or shorted. These devices also feature pin-selectable
transmitter slew rates for both RS-232 and RS-485/422
modes. Slew-rate limiting minimizes EMI and reduces
reflections caused by improperly terminated cables,
allowing error-free data transmission up to 250kbps.
Disabling slew-rate limiting allows these devices to
transmit at data rates up to 10Mbps in RS-485/422
mode and up to 1Mbps in RS-232 mode. The
MAX3160/MAX3161/MAX3162 feature a 1µA shutdown
mode, and short-circuit limiting and thermal shutdown
circuitry to protect against excessive power dissipation.

The MAX3160/MAX3162 offer a flow-through pinout that
facilitates board layout. The MAX3160/MAX3161/
MAX3162 are available in tiny SSOP packages and
operate over the commercial and extended tempera­ture ranges.

________________________Applications

Point-of-Sales Equipment Peripherals

Industrial Controls Networking

RS-232 to RS-485
Interface Converters

Features

♦ Single-Supply Operation from +3V to +5.5V

♦ Pin-Programmable as 2TX/2RX RS-232 or Single

RS-485/422 (MAX3160/MAX3161)

♦ 2TX/2RX RS-232 and Single RS-485/422

(MAX3162)

♦ Pin-Programmable RS-232/RS-485 Transmitter

Slew Rates Reduce EMI

♦ 10Mbps RS-485 and 1Mbps RS-232 Data Rates

♦ Pin-Programmable Half-Duplex or Full-Duplex

RS-485/422 Operation (MAX3160/MAX3161)

♦ RS-485/422 True Fail-Safe Receivers

♦ Transmitters and Receivers Protected Against

Wiring Faults

♦ 1µA Shutdown Supply Current
♦ 1/8-Unit Load Allows up to 256 Transceivers on

the Bus

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

________________________________________________________________

Maxim Integrated Products

1

19-1722; Rev 2; 12/09

EVALUATION KIT

AVAILABLE

Ordering Information

Typical Operating Circuit

Pin Configurations appear at end of data sheet.
Selector Guide 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.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

PART TEMP RANGE PIN-PACKAGE

MAX3160CAP+ 0°C to +70°C 20 SSOP
MAX3160EAP+ -40°C to +85°C 20 SSOP
MAX3161CAG+ 0°C to +70°C 24 SSOP
MAX3161EAG+ -40°C to +85°C 24 SSOP
MAX3162CAI+ 0°C to +70°C 28 SSOP

MAX3162EAI+ -40°C to +85°C 28 SSOP

+3V TO +5.5V

MAX3100

SPI

μP

13

11

12

10

TX

RTS

RX

CTS

SHDN

DI/T1IN

DE/T2IN

RO/R2OUT

R1OUT

16

15

8

7

1

V

CC

RS485/RS232

MAX3160

GND FAST HDPLX SHDN

4

12

11

5

13

14

910

Z(B)/T1OUT

Y(A)/T2OUT

6

A/R2IN

B/R1IN

DB9

RJ45

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3V to +5.5V, C1–C4 = 0.1µF when tested at +3.3V ±10%; C1 = 0.047µF and C2, C3, C4 = 0.33µF when tested at +5V
±10%; T

A

= T

MIN

to T

MAX

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

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.

VCCto GND..............................................................-0.3V to +6V

V+ to GND ................................................................-0.3V to +7V

V- to GND....................................................................0.3V to -7V

V+ - V- (Note 1)....................................................................+13V

Input Voltages

T1IN, T2IN, DI, DE485, RE485, TE232, RE232, SHDN,

FAST, HDPLX, RS485/RS232 to GND. ...............-0.3V to +6V

A, B, R1IN, R2IN to GND ...............................................±25V

Output Voltages

T1OUT, T2OUT, Y, Z to GND......................................±13.2V

R2OUT, R1OUT, RO to GND................-0.3V to (V

CC

+ 0.3V)

Output Short-Circuit Duration

T1OUT, T2OUT, Y, Z ............................................Continuous

Continuous Power Dissipation (T

A

= +70°C)

20-Pin SSOP (derate 11.9W/°C above +70°C) ..........952mW

24-Pin SSOP (derate 14.9W/°C above +70°C) ........1195mW

28-Pin SSOP (derate 15W/°C above +70°C) ...........1201mW

Operating Temperature Ranges

MAX316_CA_....................................................0°C to +70°C

MAX316_EA_ .................................................-40°C to +85°C

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

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

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

DC CHARACTERISTICS

VCC Standby Current I

VCC Shutdown Current I

TRANSMITTER AND LOGIC INPUTS (DI, T1IN, T2IN, DE485, RRRREEEE444488885555, TE232, RRRREEEE222233332222, FAST, HDPLX, SHDN, RS485/RRRRSSSS222233332222)

Logic Input Low V

Logic Input High V

Logic Input Leakage Current I

Transmitter Logic Hysteresis V

RS-232 AND RS-485/422 RECEIVER OUTPUTS (R1OUT, R2OUT, RO)

Receiver Output Voltage Low V

Receiver Output Voltage High V

Receiver Output Short Circuit
Current

Receiver Output Leakage
Current

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

MAX3160/MAX3161, no load,
RS485/ RS232 = GND

CC

CC

INL

HYS

I

OSR

I

OZR

OL

OH

MAX3160/MAX3161, no load,
RS485/ RS232 = V

MAX3162 No Load 3.0 6

SHDN = GND, receiver inputs open or
grounded

IL

VCC = +3.3V 2.0

IH

VCC = +5V 2.4

I

= 2.5mA 0.4 V

OUT

I

= -1.5mA V

OUT

0 < VO < V

Receivers disabled ±0.05 ±1µA

CC

CC

1.2 2.5

2.5 5.5

110µA

0.8 V

±0.01 ±1µA

0.5 V

- 0.6 V

CC

±20 ±60 mA

mA

V

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3V to +5.5V, C1–C4 = 0.1µF when tested at +3.3V ±10%; C1 = 0.047µF and C2, C3, C4 = 0.33µF when tested at +5V
±10%; T

A

= T

MIN

to T

MAX

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

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

RS-232 RECEIVER INPUTS (R1IN, R2IN)

Input Voltage Range -25 25 V

Input Threshold Low

Input Threshold High

Input Hysteresis 0.5 V

Input Resistance 357kΩ

RS-485/422 RECEIVER INPUTS (NOTE 2)

Input Resistance R

Input Current I

Input Differential Threshold V

Input Hysteresis ΔV

RS-232 TRANSMITTER OUTPUTS (T1OUT, T2OUT)

Output Voltage Swing

Output Resistance V

Output Short-Circuit Current T_OUT = GND ±30 ±60 mA

Output Leakage Current

RS-485/422 TRANSMITTER OUTPUTS (Y, Z)

Differential Output Voltage V

Change in Magnitude of
Differential Output Voltage for
Complementary Output States

Common Mode Output Voltage V

Change in Magnitude of
Common Mode Output Voltage
for Complementary Output
States

VCC = +3.3V 0.6

V

= +5V 0.8

CC

V

=+3.3V 2.0

CC

V

= +5V 2.4

CC

-7V < VCM < +12V

IN

MAX3160

IN

MAX3161/MAX3162

TH

TH

Both transmitter outputs loaded with 3kΩ
to GND

= V + = V - = 0V , V

ΔV

Δ V

OD

OD

OC

C C

V

= ±12V

OUT

TE232 = GND or SHDN =
GND

Figure 1

R = 27Ω or 50Ω, Figure 1 -0.2 0.2 V

R = 27Ω or 50Ω, Figure 1 3 V

R = 27Ω or 50Ω, Figure 1 0.2 V

OC

T 1OU T

MAX3160 48

MAX3161/
MAX3162

VCM = +12V 0.25

= -7V -0.15

V

CM

VCM = +12V 0.125

= -7V -0.075

V

CM

= V

= + 2V 300 10M Ω

T 2OU T

MAX3160/
MAX3161

MAX3162 ±25

R = 27Ω
(RS-485)

R = 50Ω
(RS-422)

96

-200 -50 mV

30 mV

±5 ±5.4 V

1.5

2

±125

V

V

kΩ

mA

µA

V

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3V to +5.5V, C1–C4 = 0.1µF when tested at +3.3V ±10%; C1 = 0.047µF and C2, C3, C4 = 0.33µF when tested at +5V
±10%; T

A

= T

MIN

to T

MAX

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

Output Short-Circuit Current I

Output Leakage Current

RS-232 TIMING CHARACTERISTICS (FAST = GND, 250kbps, ONE TRANSMITTER SWITCHING)

Maximum Data Rate RL = 3kΩ, CL = 1000pF 250 kbps

Receiver Propagation Delay R_IN to R_OUT, CL = 150pF 0.15 µs

Receiver Output Enable Time 200 ns

Receiver Output Disable Time 200 ns

Transmitter Skew |t

Receiver Skew |t

Transition-Region Slew Rate

RS-232 TIMING CHARACTERISTICS (FAST = VCC, 1Mbps, ONE TRANSMITTER SWITCHING)

Maximum Data Rate

Receiver Propagation Delay R_IN to R_OUT, CL = 150pF 0.15 µs

Receiver Output Enable Time 200 ns

Receiver Output Disable Time 200 ns

Transmitter Skew |t

Receiver Skew |t

Transition-Region Slew Rate

RS-485/422 TIMING CHARACTERISTICS (FAST = GND) 250kbps

Driver Propagation Delay

Driver Rise and Fall Time

Driver Propagation Delay Skew t

Driver Output Enable Time t

Driver Output Disable Time t

Receiver Propagation Delay

Receiver Propagation Delay
Skew

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SC

I

O

VY or VZ = +12V to –7V ±250 mA

VY or VZ = +12V,
DE485 = GND or SHDN =
GND

- t

PHL

PLH

V

CC

=3kΩ to 7kΩ, measured

R

L

| 100 ns

PLH

- t

|50ns

PHL

= +3.3V, TA = +25°C,

from +3.0V or –3.0V to
+3.0V

MAX3160/
MAX3161

±125

MAX3162 ±25

CL = 150pF
to 1000pF

= 150pF

C

L

to 2500pF

630

430

VCC = +3V to +4.5V, RL = 3kΩ, CL = 250pF 1

= +4.5V to +5.5V, RL = 3kΩ,

V

CC

= 1000pF

C

L

- t

PHL

PLH

V

CC

= 150pF to 1000pF, measured from

C

L

|25ns

PLH

- t

|50ns

PHL

= +3.3V, TA = +25°C, RL =3kΩ to 7kΩ,

1

24 150 V/μs

+3.0V or –3.0V to +3.0V

t

,

DPHL

t

DPLH

t

DPHL

t

DPLH

DSKEW

DZH

DLZ

t

RPLH,

t

RPHL

t

RSKEW

, t

, t

R

= 54Ω, CL = 50pF, Figures 3, 5 200 400 800 ns

DIFF

,

R

= 54Ω, CL = 50pF, Figures 3, 5 200 400 800 ns

DIFF

R

= 54Ω, CL = 50pF, Figure 3, 5 200 ns

DIFF

RZLRDIFF

DHZRDIFF

= 54Ω, CL = 50pF, Figures 4, 6 400 800 ns

= 54Ω, CL = 50pF, Figure 4, 6 200 400 ns

CL = 15pF, Figures 7, 9 25 80 150 ns

CL = 50pF, Figures 7, 9 10 ns

µA

V/µs

Mbps

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3V to +5.5V, C1–C4 = 0.1µF when tested at +3.3V ±10%; C1 = 0.047µF and C2, C3, C4 = 0.33µF when tested at +5V
±10%; T

A

= T

MIN

to T

MAX

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

Typical Operating Characteristics

(VCC= +3.3V, 250kbps data rate, 0.1µF capacitors, all RS-232 transmitters (RS-232 mode) loaded with 3kΩ to ground, TA= +25°C,
unless otherwise noted.)

-10.0

-7.5

-5.0

-2.5

0

2.5

5.0

7.5

10.0

0 1000 2000 3000 4000 5000

RS-232 TRANSMITTER OUTPUT VOLTAGE vs.

LOAD CAPACITANCE (FAST = GND)

MAX3160/2 TOC1

LOAD CAPACITANCE (pF)

TRANSMITTER OUTPUT VOLTAGE (V)

-10.0

-7.5

-5.0

-2.5

0

2.5

5.0

7.5

10.0

0 500 1000 1500 2000

RS-232 TRANSMITTER OUTPUT VOLTAGE

vs. LOAD CAPACITANCE (FAST =

VCC)

MAX3160/2 TOC2

LOAD CAPACITANCE (pF)

TRANSMITTER OUTPUT VOLTAGE (V)

0

4

2

10

8

6

16

14

12

18

0 20001000 3000 4000 5000

RS-232 TRANSMITTER SLEW RATE vs.

LOAD CAPACITANCE (FAST = GND)

MAX3160/2 TOC3

LOAD CAPACITANCE (pF)

SLEW RATE (V/μs)

Note 2: Applies to A, B for MAX3162 and MAX3160/MAX3161 with HDPLX = GND, or Y, Z for MAX3160/MAX3161 with HDPLX = V

CC.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Receiver Output Enable Time t

Receiver Output Disable Time t

RZL

RLZ

, t

RZHCL

, t

RHZCL

= 50pF, Figures 2, 8 100 ns

= 50pF, Figures 2, 8 100 ns

RS-485/RS-422 TIMING CHARACTERISTICS (FAST = VCC, 10Mbps)

t

Driver Propagation Delay

Driver Rise And Fall Times tDR, t

Driver Propagation Delay Skew t

Driver Output Enable Time

Driver Output Disable Time t

Receiver Propagation Delay

Receiver Propagation Delay
Skew
Receiver Output Enable Time t

Receiver Output Disable Time t

DPHL,

t

DPLH

DSKEW

t

DLZ

t

RPLH

t

RPHL

t

RSKEW

RZL

RLZ

DZL

, t

, t
, t

R

= 54Ω, CL = 50pF, Figures 3, 5 60 120 ns

DIFF

DFRDIFF

DHZRDIFF

,

= 54Ω, CL = 50pF, Figures 3, 5 10 25 ns

R

= 54Ω, CL = 50pF, Figures 3, 5 10 ns

DIFF

R

= 54Ω, CL = 50pF, Figures 4, 6 400 800 ns

DIFF

= 54Ω, CL = 50pF, Figures 4, 6 200 400 ns

CL = 15pF, Figures 7, 9 80 150 ns

CL = 50pF, Figures 7, 9 10 ns

RZHCL

RHZ

= 50pF, Figures 2, 8 100 ns

CL = 15pF, Figures 2, 8 100 ns

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VCC= +3.3V, 250kbps data rate, 0.1µF capacitors, all RS-232 transmitters (RS-232 mode) loaded with 3kΩ to ground, TA= +25°C,
unless otherwise noted.)

0

30

20

10

40

50

60

70

80

90

100

0 500 1000 1500 2000

RS-232 TRANSMITTER SLEW RATE

vs. LOAD CAPACITANCE (FAST = V

CC

)

MAX3160/2 TOC4

LOAD CAPACITANCE (pF)

SLEW RATE (V/μs)

0

20

10

40

30

50

60

0 20001000 3000 4000 5000

OPERATING SUPPLY CURRENT vs.

LOAD CAPACITANCE WHEN

TRANSMITTING DATA (RS-232 MODE)

MAX3160/2 TOC5

LOAD CAPACITANCE (pF)

SUPPLY CURRENT (mA)

1Mbps

250kbps

20kbps

0

1.0

2.0

1.5

2.5

3.0

-40 10-15 35 60 85

MAX3160/MAX3161

NO-LOAD SUPPLY CURRENT vs.

TEMPERATURE

MAX3160/2 TOC6

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

RS-485 MODE

RS-232 MODE

SHUTDOWN CURRENT vs. TEMPERATURE

160

140

120

100

80

60

SHUTDOWN CURRENT (nA)

40

20

0

-40 -15 10 35 60 85
TEMPERATURE (°C)

140

120

MAX3160/2 TOC7

100

80

60

OUTPUT CURRENT (mA)

40

20

RS-485/422 DRIVER OUTPUT CURRENT vs.

DIFFERENTIAL OUTPUT VOLTAGE

100

10

1

0.1

OUTPUT CURRENT (mA)

0.01

0.001
0 1.0 1.50.5 2.0 2.5 3.0 3.5 4.0

OUTPUT VOLTAGE (V)

3.5

3.4

3.3

MAX3160/2 TOC10

3.2

3.1

3.0

2.9

OUTPUT VOLTAGE (V)

2.8

2.7

2.6

2.5

DRIVER OUTPUT VOLTAGE

0

0462 8 10 12

OUTPUT LOW VOLTAGE (V)

RS-485/422 DRIVER DIFFERENTIAL OUTPUT

vs. TEMPERATURE

R = 50Ω

-40 10-15 35 60 85
TEMPERATURE (°C)

RS-485/422 OUTPUT CURRENT vs.

180

160

MAX3160/2 TOC8

140

120

100

OUTPUT CURRENT (mA)

MAX3160/2 TOC11

OUTPUT CURRENT (mA)

RS-485/422 OUTPUT CURRENT vs.

DRIVER OUTPUT HIGH VOLTAGE

80

60

40

20

0

-7 -3-5 -1 1 3 5
OUTPUT HIGH VOLTAGE (V)

OUTPUT CURRENT vs. RECEIVER

OUTPUT LOW VOLTAGE

30

25

20

15

10

5

0

0 1.5 2.00.5 1.0 2.5 3.0 3.5

OUTPUT LOW VOLTAGE (V)

MAX3160/2 TOC9

MAX3160/2 TOC12

MAX3160/MAX3161/MAX3162

0

40

20

80

60

100

120

-40 10-15 35 60 85

RS-485/422 RECEIVER PROPAGATION DELAY

vs. TEMPERATURE

MAX3160/2 TOC16

TEMPERATURE (°C)

PROPAGATION DELAY (ns)

CL = 50pF

RISING

FALLING

50

60

55

70

65

80

75

85

-40 10-15 35 60 85

RS-485/422 DRIVER PROPAGATION DELAY

vs.TEMPERATURE (FAST)

MAX3160/2 TOC18

TEMPERATURE (°C)

R = 50

Ω

TIME (ns)

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

_______________________________________________________________________________________

7

Typical Operating Characteristics (continued)

(VCC= +3.3V, 250kbps data rate, 0.1µF capacitors, all RS-232 transmitters (RS-232 mode) loaded with 3kΩ to ground, TA= +25°C,
unless otherwise noted.)

-1000

-800

-400

-600

0

200

-200

400

-20 -10 -5-15 0 5 10 15 20

I-V OUTPUT IMPEDANCE CURVE

IN RS-232 SHUTDOWN MODE

MAX3160-A

VOLTS (V)

CURRENT (μA)

OUTPUT CURRENT vs. RECEIVER

14

12

10

8

6

OUTPUT CURRENT (mA)

4

2

0

500

480

460

440

420

400

TIME (ns)

380

360

340

320

300

OUTPUT HIGH VOLTAGE

0 1.0 1.50.5 2.0 2.5 3.0 3.5

OUTPUT HIGH VOLTAGE (V)

RS-485/422 DRIVER PROPAGATION DELAY

vs. TEMPERATURE (SLOW)

R = 50Ω

-40 10-15 35 60 85
TEMPERATURE (°C)

MAX3160/2 TOC13

MAX3160/2 TOC19

RS-485/422

RS-485/422

DRIVER PROPAGATION

(FAST, 10Mbps)

20ns/div

MAX3160/2 TOC20

RECEIVER PROPAGATION

(FAST, 5Mbps)

MAX3160/2 TOC22

DI
5V/div

V

Y-VZ

2V/div

RS-485/422 DRIVER PROPAGATION

(SLOW, 250kbps)

RS-485/422

TO DRIVER OUTPUT

1.0μs/div

DRIVER DISABLE/ENABLE

MAX3160/2 TOC21

MAX3160/2 TOC24

DI
5V/div

VY-V

Z

2V/div

C

L

= 50pF

40ns/div

VY-V
2V/div

RO
2V/div

Z

R = 50Ω

= 82pF

C

L

100ns/div

DE485
2V/div

- V

V

Y

2V/div

Z

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

8 _______________________________________________________________________________________

Pin Description

PIN

MAX3160 MAX3161 MAX3162

1 1 1 C1+ Positive Terminal of the Positive Flying Capacitor

222V

3 3 3 C1- Negative Terminal of the Positive Flying Capacitor

4 4 4 GND Ground

— 5 5 T1OUT RS-232 Driver Output

5 — — Z(B)/T1OUT

— — 6 Z Inverting RS-485/422 Driver Output

— 6 — Z(B)

6 — — Y(A)/T2OUT

— — 7 Y Noninverting RS-485/422 Driver Output

— 7 — Y(A)

7 9 9 R1OUT RS-232 Receiver Output

— 8 8 T2OUT RS-232 Driver Output

8 10 — RO/R2OUT RS-485/422 Receiver Output/RS-232 Receiver Output

91113SHDN

— — 10 R2OUT RS-232 Driver Output

10 12 14 FAST

— — 11 RO RS-485/422 Receiver Output

11 13 — RS485/RS232

NAME FUNCTION

CC

Positive Supply Voltage

Inverting RS-485/422 Driver Output in Full-Duplex Mode
(and Inverting RS-485/422 Receiver Input in Half-Duplex
Mode)/RS-232 Driver Output

Inverting RS-485/422 Driver Output in Full-Duplex Mode
(and Inverting RS-485/422 Receiver Input in Half-Duplex
Mode)

Noninverting RS-485/422 Driver Output in Full-Duplex
Mode (and Noninverting RS-485/422 Receiver Input in
Half-Duplex Mode)/RS-232 Driver Output

Noninverting RS-485/422 Driver Output in Full-Duplex
Mode (and Noninverting RS-485/422 Receiver Input in
Half-Duplex Mode)

Active-Low Shutdown-Control Input. Drive low to shut
down transmitters and charge pump.

Select slew rate limiting for both RS-232 and RS­485/422. Slew rate limits with a logic-level low.

Software-Programmable Pin Functionality. Operates as
RS-485/422 with a logic-level high; operates as RS-232
with a logic-level low.

——12RE485

12 14 — HDPLX

RS-485/422 Receiver Enable. Logic-level low enables
RS-485/422 receivers.

Software-Programmable Pin Functionality. Operates in
full-duplex mode when low; operates in half-duplex
mode when high.

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

_______________________________________________________________________________________ 9

Pin Description (continued)

PIN

MAX3160 MAX3161 MAX3162

13 — — A/R2IN

14 — — B/R1IN

——15RE232

— 15 17 A Noninverting RS-485/422 Receiver Input

15 19 — DE485/T2IN RS-485/RS-422 Driver Enable/RS-232 Driver Input

— — 16 TE232 RS-232 Transmitter Output Enable

— 16 18 B Inverting RS-485/422 Receiver Input

16 20 — DI/T1IN RS-485/RS-422 Driver Input/RS-232 Driver Input

— 17 19 R2IN RS-232 Receiver Input

17 21 25 V- Negative Charge-Pump Rail

— 18 20 R1IN RS-232 Receiver Input

18 22 26 C2- Negative Terminal of the Negative Flying Capacitor

19 23 27 C2+ Positive Terminal of the Negative Flying Capacitor

20 24 28 V+ Positive Charge-Pump Rail

— — 21 T2IN RS-232 Driver Input

— — 22 DE485 RS-485/RS-422 Driver Enable

— — 23 DI RS-485/RS-422 Driver Input

— — 24 T1IN RS-232 Driver Input

NAME FUNCTION

Noninverting RS-485/422 Receiver Input/RS-232
Receiver Input

Inverting RS-485/422 Receiver Input/RS-232 Receiver
Input

RS-232 Receiver Enable. Logic-level low enables RS­232 receivers.

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

10 ______________________________________________________________________________________

Functional Diagrams

MAX3160

V

CC

C1

C

BYPASS

RS-232

OUTPUTS

LOGIC

OUTPUTS

RS-232 MODE

C1+

1

V

CC

2

C1-

3

GND

4

5

6

7

8

SHDN

FAST RS485/RS232

CHARGE

PUMP

T1

T2

R1

R2

C2+

C2-

HDPLX

V+

20

C3

19

C2

18

V-

17

C4

16

LOGIC
INPUTS

15

14

RS-232
INPUTS

13

129

1110

V

CC

C1

RS-485

OUTPUTS

OUTPUT

C

BYPASS

LOGIC

RS-485 MODE

C2+

C2-

D

DE

B

A

RS485/RS232

V+

20

19

18

V-

17

16

15

14

13

12

11

C3

C4

LOGIC
INPUTS

RS-485
INPUTS

HALF/FULL
DUPLEX

C2

C1+

1

V

CC

2

C1-

3

GND

4

5

6

7

R0

8

SHDN

9

10

FAST

CHARGE

PUMP

Z

Y

R

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

______________________________________________________________________________________ 11

Functional Diagrams (continued)

C1

C

BYPASS

C3

C2

C4

24

23

22

21

20

19

16

15

1

2

3

4

RS-485

OUTPUTS

LOGIC
INPUTS

LOGIC

OUTPUT

RS-485
INPUTS

SHDN

FAST RS485/RS232

5

6

9

10

18

17

7

8

V+

C2+

C2-

V-

C1-

GND

V

CC

V

CC

C1+

14

13

11

12

CHARGE

PUMP

Z

Y

B

DE

A

RS-485 MODE

D

HALF/FULL
DUPLEX

R

R0

24

23

22

21

20

19

18

17

1

2

3

4

RS-232

OUTPUT

RS-232

OUTPUT

LOGIC
INPUTS

LOGIC

OUTPUTS

RS-232
INPUTS

C1

C3

C2

C4

SHDN

HDPLX

FAST RS485/RS232

5

6

7

8

16

V+

C2+

C2-

V-

C1-

GND

V

CC

V

CC

C1+

14

13

11

12

CHARGE

PUMP

T1

T2

R1

R2

C

BYPASS

RS-232 MODE

15

9

10

MAX3161

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

12 ______________________________________________________________________________________

Functional Diagrams (continued)

MAX3162

Figure 3. RS-485/422 Driver Timing Test Circuit

1k

C

L

V

CC

TEST POINT

RECEIVER

OUTPUT

S1

1k

S2

Figure 2. RS-485/422 Receiver Enable/Disable Timing Test Load

Figure 1. RS-485/422 Driver DC Test Load

V

OD

V

OC

R

R

Z

Y

Test Circuits

V

CC

C1

C

BYPASS

RS-232

OUTPUT

RS-485

OUTPUTS

RS-232

OUTPUT

LOGIC

OUTPUTS

C1+

1

V

CC

2

C1-

3

GND

4

5

Z

6

Y

7

8

R1

9

R2

10

11

RE485

12

CHARGE

PUMP

D

RO

R

T1

DE485

T2

V+

28

20

19

18

17

27

26

25

24

23

22

211

C3

C2

C4

LOGIC
INPUTS

RS-232
INPUTS

RS-485
INPUTS

C2+

C2-

V-

B

A

SHDN

13

14

FAST

TE232

16

15

3V

DE485

DI

C

L

Y

R

V

DIFF

OD

Z

C

L

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

______________________________________________________________________________________ 13

Test Circuits (continued)

Figure 4. RS-485/422 Driver Enable/Disable Timing Test Load

Figure 5. RS-485/422 Driver Propagation Delays

Figure 6. RS-485/422 Driver Enable and Disable Times

Figure 7. RS-485/422 Receiver Propagation Delays

Figure 9. RS-485/422 Receiver Propagation Delays Test Circuit

Figure 8. MAX3162 RS-485/422 Receiver Enable and Disable
Times

V

CC

OUTPUT

UNDER TEST

500Ω

C

L

S1

S2

3V

DE485

Y, Z

V

Y, Z

1.5V 1.5V

0

t

DZL

2.3V

OL

0

OUTPUT NORMALLY LOW

OUTPUT NORMALLY HIGH

2.3V

t

DZH

t

DLZ

V

+0.5V

OL

V

-0.5V

OH

t

DHZ

3V

DI

V

DIFF

RO

1V

-1V

1.5V

0

Z

V

O

Y

1/2 V

V

O

0

-V

O

V

OH

V

OL

A

B

O

10%

T

DR

t

DPLH

V

90%

t

DSKEW = | tDPLH

/2 VCC/2

V

CC

t

RPHL

DIFF

INPUT

= Vy - V

OUTPUT

t

DPHL

z

90%

T

DF

- t

DPHL

|

t

RPLH

1.5V

10%

1/2 V

O

3V

RE485

V

RO

RO

CC

1.5V 1.5V

0

t

RZL

1.5V

OUTPUT NORMALLY LOW

OUTPUT NORMALLY HIGH

0

1.5V

t

RZH

t

RLZ

VOL + 0.5V

V

- 0.5V

OH

t

RHZ

B

V

ID

R

A

RO

C

L

MAX3160/MAX3161/MAX3162

Detailed Description

The MAX3160/MAX3161/MAX3162 3V/5V, multiprotocol
transceivers can be pin configured in a number of RS­232 and RS-485/422 interface combinations. These cir­cuit configurations are ideal for the design of RS-232 to
RS-485 converters, multiprotocol buses, or any applica­tion that requires both RS-232 and RS-485 transceivers.
The slew rate of these devices is on-the-fly pin pro­grammable, allowing reduced EMI data rates, or up to
10Mbps RS-485 communications. Power consumption
can be reduced to 1µA by using the shutdown function,
but the RS-232 receivers remain active allowing other
devices to query the interface controller. A flow-through
pinout and the space-saving SSOP packages (avail­able in the commercial and extended temperature
ranges) facilitate board layout.

Device Selection

The MAX3160/MAX3161/MAX3162 contain RS-232
transceivers and an RS-485/422 transceiver. The pri­mary difference between the devices is the multiplexing
of the I/O pins.

The MAX3160 has common transmitter outputs and
receiver inputs for its RS-232 and RS-485/422 trans­ceivers, and common digital I/O pins. The MAX3160 is
optimized for multiprotocol operation on a single inter­face bus and comes in a 20-pin SSOP.

The MAX3161 has separate transmitter outputs and
receiver inputs for its RS-232 and RS-485/422 trans­ceivers, and common digital I/O pins. The MAX3161 is
optimized for multiplexing a single UART across two
interface buses and comes in a 24-pin SSOP.

The MAX3162 has separate transmitter outputs and
receiver inputs for its RS-232 and RS-485/422 trans­ceivers, and separate digital I/O pins. The MAX3162 is
optimized for protocol translation between two interface
buses and comes in a 28-pin SSOP.

See Tables 1–12,

Functional Diagrams

, and the follow-

ing descriptions for details on each device.

MAX3160

The MAX3160 is a 2TX/2RX RS-232 transceiver in RS­232 mode, capable of RS-232-compliant communica­tion. Assertion of RS-485/RS232 converts the device to
a single RS-485 transceiver by multiplexing the RS-232
I/O pins to an RS-485 driver and receiver pair. The
logic inputs now control the driver input and the driver
enable. One logic output carries the RS-485 receiver
output, and the other is three-stated. The receiver input
impedance is dependent on the device mode and is
1/4-unit load for RS-485 operation and 5kΩ for RS-232
operation.

MAX3161

The MAX3161 is a 2TX/2RX RS-232 transceiver in RS­232 mode or a single RS-485/422 transceiver in RS-485
mode. When in RS-485 mode, the unused RS-232
transmitter and receiver output pins are disabled. When
in RS-232 mode, the RS-485 transmitter outputs are
disabled and the RS-232 receiver inputs are 5kΩ to
GND. The RS-485 receiver inputs are always 1/8-unit
load. Logic lines are shared between the two protocols
and are used for signal inputs and as an RS-485 driver
enable.

MAX3162

The MAX3162 is a 2TX/2RX RS-232 transceiver and a
single RS-485/422 transceiver simultaneously. All dri­vers, receivers, and transmitters can be enabled or dis­abled by pin configuration. All outputs are high-Z when
not activated. RS-232 receiver inputs are 5kΩ when
enabled, and RS-485 receiver inputs are 1/8-unit load.

FAST Mode operation

The FAST control pin is used to select the slew-rate lim­iting of the RS-232 transmitters and the RS-485/422 dri­vers. With FAST unasserted, the RS-232 transmitters
and the RS-485/422 driver are slew-rate limited to
reduce EMI. RS-232 data rates up to 1Mbps and RS­485/422 data rates up to 10Mbps are possible when
FAST is asserted. FAST can be changed during opera­tion without interrupting data communications.

Half-Duplex RS-485/422 Operation

Asserting HDPLX places the MAX3160/MAX3161 in
half-duplex mode. The RS-485 receiver inputs are inter­nally connected to the driver outputs. The RS-485 dri­ver outputs can be disabled by pulling DE485 low.
HDPLX has no affect on RS-232 operation.

Low-Power Shutdown

The MAX3160/MAX3161/MAX3162 have an active-low
shutdown control input, SHDN. When driven low, the
charge pump and transmitters are shut down and sup­ply current is reduced to 1µA. The RS-232 receiver out­puts remain active if in RS-232 mode. The charge­pump capacitors must be recharged when coming out
of shutdown before resuming operation in either RS-232
or RS-485/422 mode (Figure 10).

Dual Charge-Pump Voltage Converter

The MAX3160/MAX3161/MAX3162s’ internal power
supply consists of a regulated dual charge pump that
provides output voltages of +5.5V (doubling charge
pump) and -5.5V (inverting charge pump) for input volt­ages (VCC) over the 3.0V to 5.5V range. The charge
pumps operate in a discontinuous mode: if the magni­tude of either output voltage is less than 5.5V, the

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

14 ______________________________________________________________________________________

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

______________________________________________________________________________________ 15

charge pumps are enabled; if the magnitude of both
output voltages exceeds 5.5V, the charge pumps are
disabled. Each charge pump requires a flying capaci­tor (C1, C2) and a reservoir capacitor (C3, C4) to gen­erate the V+ and V- supplies (see

Functional

Diagrams).

RS-485/422 Transceivers

The MAX3160/MAX3161/MAX3162 RS-485/422 trans­ceivers feature fail-safe circuitry that guarantees a
logic-high receiver output when the receiver inputs are
open or shorted, or when they are connected to a ter­minated transmission line with all drivers disabled (see

Fail-Safe

). The MAX3160/MAX3161/MAX3162 also fea­ture pin-selectable reduced slew-rate drivers that mini­mize EMI and reduce reflections caused by improperly
terminated cables, allowing error-free data transmission
up to 250kbps (see

RS-485/422 Reduced EMI and

Reflection

s). The transmitters may operate at speeds
up to 10Mbps with the slew-rate limiting disabled.
Drivers are short-circuit current limited and thermally
limited to protect them against excessive power dissi­pation. Half-duplex communication is enabled by dri­ving HDPLX high.

Fail-Safe

The MAX3160/MAX3161/MAX3162 guarantee a logic­high RS-485 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 having the receiver threshold between

-50mV and -200mV. If the differential receiver input volt­age (A-B) is greater than or equal to -50mV, RO is logic
high. If A-B is less than or equal to -200mV, RO is logic
low. In the case of a terminated bus with all transmitters
disabled, the receiver’s differential input voltage is
pulled to GND by the termination. This results in a logic
high with a 50mV minimum noise margin. Unlike other
fail-safe devices, the -50mV to -200mV threshold com­plies with the ±200mV EIA/TIA-485 standard.

RS-232 Transceivers

The MAX3160/MAX3161/MAX3162 RS-232 transmitters
are inverting-level translators that convert CMOS-logic
levels to ±5.0V EIA/TIA-232-compliant levels. The trans­mitters are guaranteed at a 250kbps data rate in slew­rate limited mode (FAST = GND) with worst-case loads
of 3kΩ in parallel with 1000pF. Data rates up to
1Mbps can be achieved by asserting FAST.
When powered down or in shutdown, the MAX3160/
MAX3161/MAX3162 outputs are high impedance and
can be driven to ±12V. The transmitter inputs do not
have pullup resistors. Connect unused inputs to ground
or VCC.

The receivers convert RS-232 signals to CMOS-logic out­put levels. All receivers have inverting outputs that
remain active in shutdown. The MAX3160/MAX3161/
MAX3162 permit their receiver inputs to be driven to Dia
±25V. Floating receiver input signals are pulled to
ground through internal 5kΩ resistors, forcing the out­puts to a logic high. The MAX3162 has transmitter and
receiver enable pins that allow its outputs to be three­stated.

Applications Information

Capacitor Selection

The capacitor type used for C1–C4 is not critical for
proper operation; polarized or nonpolarized capacitors
can be used. Ceramic chip capacitors with an X7R
dielectric provide the best combination of performance,
cost, and size. The charge pump requires 0.1µF
capacitors for 3.3V operation. For other supply volt­ages, see Table 13 for required capacitor values. Do
not use values smaller than those listed in Table 13.
Increasing the capacitor values reduces ripple on the
transmitter outputs and slightly reduces power con­sumption. C2, C3, and C4 can be changed without
changing C1’s value. However, do not increase C1

without also increasing the values of C2, C3, C4,
and C

BYPASS

to maintain the proper ratios to the

other capacitors.

When using the minimum required capacitor values,
make sure the capacitance value does not degrade
excessively with temperature or voltage. This is typical
of Y5V and Z5U dielectric ceramic capacitors. If in
doubt, use capacitors with a larger nominal value. The
capacitor’s equivalent series resistance (ESR), which
usually rises at low temperatures, influences the
amount of ripple on V+ and V-.

Power-Supply Decoupling

In applications that are sensitive to power-supply noise,
decouple VCCto ground with a capacitor of the same
value as reservoir capacitors C2, C3, and C4. Connect
the bypass capacitor as close to the IC as possible.

RS-232 Transmitter Outputs

when Exiting Shutdown

Figure 10 shows two transmitter outputs when exiting
shutdown mode. As they become active, the two trans­mitter outputs are shown going to opposite RS-232 lev­els (one transmitter input is high, the other is low). Each
transmitter is loaded with 3kΩ in parallel with 1000pF.
The transmitter outputs display no ringing or undesir­able transients as they come out of shutdown. Note that
the transmitters are enabled only when V- exceeds
approximately -3V.

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

16 ______________________________________________________________________________________

High Data Rates

The MAX3160/MAX3161/MAX3162 maintain the RS-232
±5.0V required minimum transmitter output voltage even
at high data rates. Figure 11 shows a transmitter loop­back test circuit. Figure 12 shows a loopback test result
at 250kbps, and Figure 13 shows the same test at
1000kbps. Figure 12 demonstrates a single slew-rate
limited transmitter driven at 250kbps (FAST = GND) into
an RS-232 load in parallel with 1000pF. Figure 13 shows

a single transmitter driven at 1Mbps (FAST asserted),
loaded with an RS-232 receiver in parallel with 1000pF.
These transceivers maintain the RS-232 ±5.0V minimum
transmitter output voltage at data rates up to 1Mbps.

256 Transceivers on the Bus

The standard RS-485 receiver input impedance is 12kΩ
(one-unit load), and the standard driver can drive up to
32-unit loads. The MAX3160 has a 1/4-unit load receiv­er input impedance (48kΩ), allowing up to 128 trans-

Table 1. MAX3160

Table 2. MAX3161

Table 3. MAX3162

Table 4. MAX3160

Table 5. MAX3161

RS-232 Transmitters

Table 6. MAX3162

RS-232 Receivers

Truth Tables

INPUTS OUTPUTS

SHDN

0 X X 1/8 Unit Load

10 0 1

10 1 0

1 1 X RS-485 Mode

RS485

RRRRSSSS2222333322

22

DI/T1IN,

DE485/T2IN

Z(B)/T1OUT,
Y(A)/T2OUT

SHDN

X0 0 1

X0 1 0

X 0 Inputs Open 1

X1 X

INPUTS OUTPUTS

SHDN

0 X X High-Z

10 0 1

10 1 0

1 1 X High-Z

RS-485/

RS-232

DI/T1IN,

DE485/T2IN

T1OUT,

T2OUT

SHDN

X0 0 1

X0 1 0

X 0 Inputs Open 1

X1 X

INPUTS OUTPUTS

RS-485/

22

RRRRSSSS----2222333322

INPUTS OUTPUTS

RS-485/

22

RRRRSSSS----2222333322

B/R1IN,

A/R2IN

R1IN, R2IN

R1OUT,

RO/R2OUT

R1OUT

High-Z,

RO/R2OUT in

RS-485 mode

R1OUT,

RO/R2OUT

R1OUT

High-Z,

RO/R2OUT in
RS-485 mode

INPUTS OUTPUTS

SHDN TE232 T1IN,T2IN

0 X X High-Z
X 0 X High-Z
11 0 1

11 1 0

T1OUT,

T2OUT

INPUTS OUTPUTS

SHDN RE232 R1IN, R2IN

X 1 X High-Z

X0 0 1

X0 1 0

X 0 Inputs open 1

R1OUT,

R2OUT

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

______________________________________________________________________________________ 17

Table 7. MAX3160

Table 8. MAX3161

Table 9. MAX3162

Table 10. MAX3160

*

Y and Z correspond to pins Y(A)/T2OUT and Z(B)/T1OUT. A and B correspond to pins A/R2IN and B/R1IN.

Truth Tables (continued)

RS-485/422 Receivers

RS-485/422 Drivers

SHDN RS485/RRRRSSSS2222333322

0 1 X X 1/8 Unit Load 1/8 Unit Load

1 1 0 X 1/8 Unit Load 1/8 Unit Load

1110 1 0

1111 0 1

X 0 X X RS-232 Mode

SHDN RS485/RRRRSSSS2222333322

0 X X X 1/8 Unit Load 1/8 Unit Load

X 0 X X 1/8 Unit Load 1/8 Unit Load

X X 0 X 1/8 Unit Load 1/8 Unit Load

1110 1 0

1111 0 1

SHDN DE485 DI Z Y

0 X X High-Z High-Z

X 0 X High-Z High-Z

110 1 0

111 0 1

INPUTS OUTPUTS

22

INPUTS OUTPUTS

22

INPUTS OUTPUTS

DE485/T2IN DI/T1IN Z(B)/T1OUT Y(A)/T2OUT

DE485/T2IN DI/T1IN Z(B) Y(A)

INPUTS OUTPUT

RS485/RS232 SHDN HDPLX A - B* Y - Z* RO/R2OUT

1 0 X X X High-Z Up to V

110≥-50mV X 1

110≤-200mV X 0

1 1 0 Floating X 1

111X≥-50mV 1

111X≤-200mV 0

1 1 1 X Floating 1

0 X X X X RS-232 Mode

CC

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

18 ______________________________________________________________________________________

ceivers to be connected in parallel on one communica­tion line. The MAX3161/MAX3162 have a 1/8-unit load
receiver input impedance (96kΩ), allowing up to 256
transceivers to be connected in parallel on one com­munication line. Any combination of these devices
and/or other RS-485 transceivers with a total of 32-unit
loads or fewer can be connected to the line.

The MAX3160/MAX3161/MAX3162 RS-485 driver out­puts are 1/8-unit load when disabled This impedance
may be reduced if the D1 pin is toggled at a high fre­quency. With no power applied (VCC= GND), the RS­485 transmitter output impedances typically go to 1/2­unit load on the MAX3161/MAX3162, and to one-unit
load on the MAX3160.

Driver Output Protection

Two mechanisms prevent excessive output current and
power dissipation caused by faults or by bus con­tention. The first, a foldback current limit on the output
stage, provides immediate protection against short cir­cuits over the whole common-mode voltage range (see

Typical Operating Characteristics

). The second, a ther­mal shutdown circuit, forces the driver outputs into a
high-impedance state if the die temperature becomes
excessive.

Protection Against Wiring Faults

EIA/TIA-485 standards require a common input voltage
range of -7V to +12V to prevent damage to the device.
The MAX3160/MAX3161/MAX3162 inputs are protected
to RS-232 levels of ±25V for the receiver inputs and
±13.2V for the transmitter/driver outputs. This provides
additional protection for the RS-485 transceivers
against ground differential or faults due to miswiring.

RS-485/422 Reduced EMI and Reflections

The MAX3160/MAX3161/MAX3162 can be configured
for slew-rate limiting by pulling FAST low. This minimizes
EMI and reduces reflections caused by improperly ter­minated cables. Operation in slew-rate limited mode
reduces the amplitudes of high-frequency harmonics.

Table 13. Required Minimum Capacitance
Values

Table 11. MAX3161

Table 12. MAX3162

Truth Tables (continued)

INPUTS OUTPUT

RS485/RS232 SHDN HDPLX A - B Y(A) - Z(B) RO/R2OUT

1 0 X X X High-Z up to V

1 1 0 -50mV X 1

1 1 0 -200mV X 0

1 1 0 Floating X 1

1 1 1 X -50mV 1

1 1 1 X -200mV 0

1 1 1 X Floating 1

0 X X X X RS-232 Mode

INPUTS OUTPUT

SHDN RE485 A - B RO

0 X X High-Z

X 1 X High-Z

1 0 -50mV 1

1 0 -200mV 0

1 0 Inputs Open 1

SUPPLY VOLTAGE

+3.0 TO +3.6 0.1 0.1

+4.5 TO +5.5 0.047 0.33

+3.0 TO +5.5 0.1 0.47

(V)

C1 (µF)

C2, C3, C4, C

(µF)

CC

BYPASS

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

______________________________________________________________________________________ 19

RS-485/422 Line Length vs. Data Length

The RS-485/422 standard covers line lengths up to
4000 feet. For line lengths greater than 4000 feet, use
the repeater application shown in Figure 14.

RS-232/RS-485 Protocol Translator

Figure 15 shows the MAX3162 configured as an RS­232/RS-485 protocol translator. The direction of transla­tion is controlled through the RTS signal (R1IN). The

single-ended RS-232 receiver input signal is translated
to a differential RS-485 transmitter output. Similarly, a
differential RS-485 receiver input signal is translated to
a single-ended RS-232 transmitter output. RS-232 data
received on R2IN is transmitted as an RS-485 signal on
Z and Y. RS-485 signals received on A and B are trans­mitted as an RS-232 signal on T1OUT.

Multiprotocol Bus

The

Typical Operating Circuit

shows a standard appli­cation for the MAX3160. The MAX3160’s output pins
are multiplexed between RS-232 and RS-485 protocols
by a microprocessor (µP). The µP also directs the shut­down functions, enable lines, and the duplex of the
MAX3160. Data is transmitted to the MAX3100 UART
through an SPI™ port. The UART asynchronously

Figure 10. MAX3160 RS-232 Transmitter Outputs When Exiting
Shutdown

Figure 12. RS-232 Loopback Test Result at 250kbps, FAST =
Low

Figure 13. RS-232 Loopback Test Result at 1000kbps, FAST =
High

Figure 11. Loopback Test Circuit

SPI is a trademark of Motorola, Inc.

MAX 3160-2 FIG10

40μs/div

SHDN
5V/division

T1OUT
2V/div

GND

T2OUT
2V/div

V

CC

C

BYPASS

V

CC

MAX3160
MAX3161
MAX3162

V+

C3

V-

C4

C1

C2

C1+

C1-

C2+

C2-

MAX 3160-2 FIG12

T

IN

T

OUT

5V/div

R

OUT

1μs/div

MAX 3160-2 FIG13

T

IN

T

OUT

5V/div

R

OUT

T_ IN

R_ OUT

V

CC

SHDN

GND

T_ OUT

R_ IN

1000pF

5k

200ns/div

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

20 ______________________________________________________________________________________

transfers data through the MAX3160 to the pin-selected
RS-232 or RS-485 protocol; see Table 14 for commonly
used cable connections.

Multiprotocol Bus Multiplexer

The

Typical Application Circuit

shows the MAX3161 con­figured as a multiprotocol bus multiplexer. The MAX3161
separates the RS-232 and RS-485 lines, but shares the
logic pins between modes. This application allows the
µP to monitor a point-to-point RS-232 bus, and a mul­tidrop RS-485 interface. The MAX3100 UART asynchro­nously transfers data through the MAX3161 to the
pin-selected RS-232 or RS-485 protocol.

Figure 14. RS-485 Line Repeater

Figure 15. Protocol Translator

MAX3160
MAX3161
MAX3162

A

RO

RE485

DE485

DI

NOTE: RE485 ON MAX3162 ONLY

R

D DATA OUT

120Ω

B

120Ω

Z

Y

DATA IN

RCV

RTS

27

C3
100nF

C2+

26

C2-

13

SHDN

5

T1OUT

10

R2OUT

23

DI

19

R2IN

20

R1IN

15

RE232

16

TE232

14

FAST

28

V+

C2

100nF

TX

3.3V

V

CC

MAX3162

GND

4

2

C1+

C1-

T1IN

R1OUT

RE485

DE485

C

BYPASS

100nF

1

C1

3

24

11

RO

9

12

22

17

A

18

B

6

Z

7

Y

25

V-

100nF

C4
100nF

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

______________________________________________________________________________________ 21

Typical Application Circuit

Table 14. Cable Connections Commonly Used for EIA/TIA-232 and
V.24 Asynchronous Interfaces

EIA/TIA-232
STANDARD

CONNECTOR

PIN

DCD 1 Data Carrier Detect

RD 2 R2IN 13 17 19 Received Data

TD 3 T1OUT 5 5 5 Transmitted Data

DTR 4 Data Terminal Ready

SG 5 GND 4 4 4 Signal Ground

DSR 6 Data Set Ready

RTS 7 T2OUT 6 8 8

CTS 8 R1IN 14 18 20 Clear to Send (= DCE ready)

RI 9 Ring Indicator

MAX3160
MAX3161

PIN NUMBER

MAX3162

EQUIVALENT MAX3160 MAX3161 MAX3162

FUNCTION

(as seen by DTE)

Request to Send (= DTE
ready)

+

214

V

CC

HDPLX

DB9

RS-485

RS-232

1

RJ45

MAX3100

UART

SPI

μP

TX

13

RX

12

RTS

11

CTS

10

DI/T1IN

20

RO/R2OUT

10

DE/T2IN

19

R1OUT R1IN

9

GND FAST SHDN

412

RS-485/RS-232

SHDN

MAX3161

T1OUT

5

R2IN

17

T2OUT

8

18

Y(A)

7

Z(B)

6

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422
Multiprotocol Transceivers

22 ______________________________________________________________________________________

Pin Configurations

Selector Guide Chip Information

PROCESS: BiCMOS

PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

20 SSOP A20+1

21-0056

24 SSOP A24+3

21-0056

28 SSOP A28+3

21-0056

Package Information

For the latest package outline information and land patterns,
go to www.maxim-ic.com/packages

. Note that a “+”, “#”, or
“-” in the package code indicates RoHS status only. Package
drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.

TOP VIEW

C1+

V

C1-

Z(B)/T1OUT

Y(A)/T2OUT

R1OUT

SHDN

FAST

1

2

CC

3

4

5

6

7

8

9

10

+

MAX3160

20-PIN SSOP

20

V+

19

C2+

18

C2-

17

V-GND

16

DI/T1IN

15

DE485/T2IN

14

B/R1IN

A/R2INRO/R2OUT

13

12

HDPLX

11

RS-485/RS-232

T1OUT

R1OUT

RO/R2OUT

SHDN

C1+

V

C1-

Z(B)

Y(A)

+

1

2

CC

3

4

MAX3161

5

6

7

8

9

10

11

12

24-PIN SSOP

FLOW-

PART DUAL-MODE

THROUGH

PIN-OUT

MAX3160 No Yes 1/4
MAX3161 No No 1/8
MAX3162 Yes Yes 1/8

RS-485

INPUT UNIT

LOADS

24

23

22

21

20

19

18

17

16

15

14

13

V+

C2+

C2-

V-GND

DI/T1IN

DE485/T2IN

R1IN

R2INT2OUT

B

A

HDPLX

RS-485/RS-232FAST

+

C1+

V

C1-

GND

T1OUT

T2OUT

R1OUT

R2OUT

RE485

SHDN

FAST

1

2

CC

3

4

5

Z

Y

RO

MAX3162

6

7

8

9

10

11

12

13

14

V+

28

C2+

27

C2-

26

V-

25

T1IN

24

DI

23

DE485

22

T2IN

21

R1IN

20

R2IN

19

B

18

A

17

TE232

16

RE232

15

28-PIN SSOP

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 ____________________

23

© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

MAX3160/MAX3161/MAX3162

+3.0V to+5.5V, 1µA, RS-232/RS-485/422

Multiprotocol Transceivers

Revision History

REVISION

NUMBER

2 12/09

REVISION

DATE

DESCRIPTION

Corrected the “Continuous Power Dissipat ion” specif icat ions under the Absolute
Maximum Ratings.

Changed pin labels in the Functional Diagrams. 11

Deleted “TRANSISTOR COUNT: 1580” and added “PROCESS: BiCMOS” to the Chip
Informat ion.

PAGES

CHANGED

2

22