MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
EVALUATION KIT AVAILABLE
General Description
The MAX3160/MAX3161/MAX3162 are programmable
+3V to +5.5V RS-232/RS-485/422 multiprotocol trans-
ceivers. 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 trans-
mitter output stage and an on-board dual charge pump
to allow RS-232 and RS-485/422 compliant perfor-
mance from a +3V to +5.5V supply. These devices also
feature pin-selectable transmitter slew rates for both
RS-232 and RS-485/422 modes. Slew-rate limiting mini-
mizes EMI and reduces reflections caused by improp-
erly 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/MAX3162 offer a flow-through pinout that
facilitates board layout. The MAX3160/MAX3161/
MAX3162 are available in tiny SSOP packages and
operate from -40°C to +85°C.
Applications
Point-of-Sales Equipment Peripherals
Industrial Controls Networking
RS-232 to RS-485
Interface Converters
Benefits and Features
•Flexible Options for RS-232 and RS-422/485
Operation in One Package
•Simultaneous 2TX/2RX RS-232 and Half-Duplex
RS-485 Transceiver Operation (MAX3162)
•Pin-Programmable as Either 2TX/2RX RS-232 or
Half/Full RS-485 Transceiver (MAX3160,
MAX3161)
•Integrated Protection Increases Robustness
•Transmitters and Receivers Protected Against
Wiring Faults
•True Fail-Safe Receiver Prevents False Transition
on Receiver Input Short or Open
•Short-Circuit Protection Over the Entire Common-
Mode Voltage Range
•Thermal Protection from Excessive Power
Dissipation
•Slew Rate Limiting Minimizes EM and Reduces
Cable Reflections
•Integrated Charge-Pump Circuitry Saves Board
Space
•Eliminates the Need for a Bipolar ±12V Supply
•Enables Single-Supply Operation From +3V to
+5.5V Voltage Supply
•1µA Shutdown Supply Current Saves Power
•Allows Up to 256 Transceivers on the Bus
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
Ordering Information
Typical Operating Circuit
Pin Configurations appear at end of data sheet.
Selector Guide appears at end of data sheet.
TX
VCC
DI/T1IN Z(B)/T1OUT
R1OUT B/R1IN
GND FAST HDPLX SHDN
Y(A)/T2OUT
A/R2IN
CTS
13
10
DE/T2IN
RTS
11 15 6
RO/R2OUT
RX
12 813
714
910 12
16 5
11
RJ45
DB9
SHDN
µP
SPI
MAX3100
RS485/RS232
1
MAX3160
+3V TO +5.5V
4
+
Denotes a lead(Pb)-free/RoHS-compliant package.
19-1722; Rev 3; 5/15
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 2www.maximintegrated.com
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%; TA= TMIN to TMAX, 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.
VCC to 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 (VCC + 0.3V)
Output Short-Circuit Duration
T1OUT, T2OUT, Y, Z ............................................Continuous
Continuous Power Dissipation (TA= +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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DC CHARACTERISTICS
MAX3160/MAX3161, no load,
RS485/ RS232 = GND 1.2 2.5
MAX3160/MAX3161, no load,
RS485/ RS232 = VCC 2.5 5.5
VCC Standby Current ICC
MAX3162 No Load 3.0 6
mA
VCC Shutdown Current ICC
SHDN = GND, receiver inputs open or
grounded 110µA
TRANSMITTER AND LOGIC INPUTS (DI, T1IN, T2IN, DE485, RR
RREE
EE44
4488
8855
55, TE232, RR
RREE
EE22
2233
3322
22, FAST, HDPLX, SHDN, RS485/RR
RRSS
SS22
2233
3322
22)
Logic Input Low VIL 0.8 V
VCC = +3.3V 2.0
Logic Input High VIH VCC = +5V 2.4 V
Logic Input Leakage Current IINL ±0.01 ±1µA
Transmitter Logic Hysteresis VHYS 0.5 V
RS-232 AND RS-485/422 RECEIVER OUTPUTS (R1OUT, R2OUT, RO)
Receiver Output Voltage Low VOL IOUT = 2.5mA 0.4 V
Receiver Output Voltage High VOH IOUT = -1.5mA VCC - 0.6 V
Receiver Output Short Circuit
Current IOSR 0 < VO < VCC ±20 ±60 mA
Receiver Output Leakage
Current IOZR Receivers disabled ±0.05 ±1µA
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 3www.maximintegrated.com
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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
RS-232 RECEIVER INPUTS (R1IN, R2IN)
Input Voltage Range -25 25 V
VCC = +3.3V 0.6
Input Threshold Low VCC = +5V 0.8 V
VCC =+3.3V 2.0
Input Threshold High VCC = +5V 2.4 V
Input Hysteresis 0.5 V
Input Resistance 357kΩ
RS-485/422 RECEIVER INPUTS (NOTE 2)
MAX3160 48
Input Resistance RIN -7V < VCM < +12V MAX3161/
MAX3162 96 kΩ
VCM = +12V 0.25
MAX3160 VCM = -7V -0.15
VCM = +12V 0.125
Input Current IIN
MAX3161/MAX3162 VCM = -7V -0.075
mA
Input Differential Threshold VTH -200 -50 mV
Input Hysteresis ΔVTH 30 mV
RS-232 TRANSMITTER OUTPUTS (T1OUT, T2OUT)
Output Voltage Swing Both transmitter outputs loaded with 3kΩ
to GND ±5±5.4 V
Output Resistance V
C C
= V + = V - = 0V , V
T 1OU T
= V
T 2OU T
= + 2V 300 10M Ω
Output Short-Circuit Current T_OUT = GND ±30 ±60 mA
MAX3160/
MAX3161 ±125
Output Leakage Current
VOUT = ±12V
TE232 = GND or SHDN =
GND MAX3162 ±25
µA
RS-485/422 TRANSMITTER OUTPUTS (Y, Z)
R = 27Ω
(RS-485) 1.5
Differential Output Voltage VOD Figure 1
R = 50Ω
(RS-422) 2
V
Change in Magnitude of
Differential Output Voltage for
Complementary Output States
ΔVOD R = 27Ω or 50Ω, Figure 1 -0.2 0.2 V
Common Mode Output Voltage VOC R = 27Ω or 50Ω, Figure 1 3 V
Change in Magnitude of
Common Mode Output Voltage
for Complementary Output
States
Δ VOC R = 27Ω or 50Ω, Figure 1 0.2 V
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 4www.maximintegrated.com
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Output Short-Circuit Current ISC VY or VZ = +12V to –7V ±250 mA
MAX3160/
MAX3161 ±125
Output Leakage Current IO
VY or VZ = +12V,
DE485 = GND or SHDN =
GND MAX3162 ±25
µA
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 |tPHL - tPLH| 100 ns
Receiver Skew |tPLH - tPHL|50ns
CL = 150pF
to 1000pF 630
Transition-Region Slew Rate
VCC = +3.3V, TA = +25°C,
RL =3kΩ to 7kΩ, measured
from +3.0V or –3.0V to
+3.0V
CL = 150pF
to 2500pF 430
V/µs
RS-232 TIMING CHARACTERISTICS (FAST = VCC, 1Mbps, ONE TRANSMITTER SWITCHING)
VCC = +3V to +4.5V, RL = 3kΩ, CL = 250pF 1
Maximum Data Rate VCC = +4.5V to +5.5V, RL = 3kΩ,
CL = 1000pF 1Mbps
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 |tPHL - tPLH|25ns
Receiver Skew |tPLH - tPHL|50ns
Transition-Region Slew Rate
VCC = +3.3V, TA = +25°C, RL =3kΩ to 7kΩ,
CL = 150pF to 1000pF, measured from
+3.0V or –3.0V to +3.0V
24 150 V/μs
RS-485/422 TIMING CHARACTERISTICS (FAST = GND) 250kbps
Driver Propagation Delay tDPHL,
tDPLH RDIFF = 54Ω, CL = 50pF, Figures 3, 5 200 400 800 ns
Driver Rise and Fall Time tDPHL,
tDPLH RDIFF = 54Ω, CL = 50pF, Figures 3, 5 200 400 800 ns
Driver Propagation Delay Skew tDSKEW RDIFF = 54Ω, CL = 50pF, Figure 3, 5 200 ns
Driver Output Enable Time tDZH, tRZL RDIFF = 54Ω, CL = 50pF, Figures 4, 6 400 800 ns
Driver Output Disable Time tDLZ, tDHZ RDIFF = 54Ω, CL = 50pF, Figure 4, 6 200 400 ns
Receiver Propagation Delay tRPLH,
tRPHL CL = 15pF, Figures 7, 9 25 80 150 ns
Receiver Propagation Delay
Skew tRSKEW CL = 50pF, Figures 7, 9 10 ns
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%; TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 5www.maximintegrated.com
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Receiver Output Enable Time tRZL, tRZH CL = 50pF, Figures 2, 8 100 ns
Receiver Output Disable Time tRLZ, tRHZ CL = 50pF, Figures 2, 8 100 ns
RS-485/RS-422 TIMING CHARACTERISTICS (FAST = VCC, 10Mbps)
Driver Propagation Delay tDPHL,
tDPLH RDIFF = 54Ω, CL = 50pF, Figures 3, 5 60 120 ns
Driver Rise And Fall Times tDR, tDF RDIFF = 54Ω, CL = 50pF, Figures 3, 5 10 25 ns
Driver Propagation Delay Skew tDSKEW RDIFF = 54Ω, CL = 50pF, Figures 3, 5 10 ns
Driver Output Enable Time tDZL RDIFF = 54Ω, CL = 50pF, Figures 4, 6 400 800 ns
Driver Output Disable Time tDLZ, tDHZ RDIFF = 54Ω, CL = 50pF, Figures 4, 6 200 400 ns
Receiver Propagation Delay tRPLH,
tRPHL CL = 15pF, Figures 7, 9 80 150 ns
Receiver Propagation Delay
Skew tRSKEW CL = 50pF, Figures 7, 9 10 ns
Receiver Output Enable Time tRZL, tRZH CL = 50pF, Figures 2, 8 100 ns
Receiver Output Disable Time tRLZ, tRHZ CL = 15pF, Figures 2, 8 100 ns
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%; TA= TMIN to TMAX, 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 3kΩto ground, TA= +25°C,
-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 = VCC.
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 6www.maximintegrated.com
0
20
40
60
80
100
120
140
160
-40 -15 10 35 60 85
SHUTDOWN CURRENT vs. TEMPERATURE
MAX3160/2 TOC7
TEMPERATURE (°C)
SHUTDOWN CURRENT (nA)
0
40
20
80
60
120
100
140
046281012
RS-485/422 OUTPUT CURRENT vs.
DRIVER OUTPUT VOLTAGE
MAX3160/2 TOC8
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
0
40
20
100
80
60
160
140
120
180
-7 -3-5 -1 1 3 5
RS-485/422 OUTPUT CURRENT vs.
DRIVER OUTPUT HIGH VOLTAGE
MAX3160/2 TOC9
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
0.001
0.01
1
0.1
10
100
0 1.0 1.50.5 2.0 2.5 3.0 3.5 4.0
RS-485/422 DRIVER OUTPUT CURRENT vs.
DIFFERENTIAL OUTPUT VOLTAGE
MAX3160/2 TOC10
OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
2.5
2.8
2.7
2.6
2.9
3.0
3.1
3.2
3.3
3.4
3.5
-40 10-15 356085
RS-485/422 DRIVER DIFFERENTIAL OUTPUT
vs. TEMPERATURE
MAX3160/2 TOC11
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
R = 50Ω
0
10
5
20
15
25
30
0 1.5 2.00.5 1.0 2.5 3.0 3.5
OUTPUT CURRENT vs. RECEIVER
OUTPUT LOW VOLTAGE
MAX3160/2 TOC12
OUTPUT LOW VOLTAGE (V)
OUTPUT CURRENT (mA)
Typical Operating Characteristics (continued)
(VCC = +3.3V, 250kbps data rate, 0.1µF capacitors, all RS-232 transmitters (RS-232 mode) loaded with 3kΩto 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 = VCC)
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
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 7www.maximintegrated.com
0
40
20
80
60
100
120
-40 10-15 356085
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 = 50Ω
TIME (ns)
300
360
340
320
380
400
420
440
460
480
500
-40 10-15 356085
RS-485/422 DRIVER PROPAGATION DELAY
vs. TEMPERATURE (SLOW)
MAX3160/2 TOC19
TEMPERATURE (°C)
TIME (ns)
R = 50Ω
RS-485/422
DRIVER PROPAGATION
(FAST, 10Mbps)
MAX3160/2 TOC20
DI
5V/div
VY-VZ
2V/div
20ns/div
1.0μs/div
MAX3160/2 TOC21
DI
5V/di
VY-V
2V/d
RS-485/422
DRIVER PROPAGATION
(FAST, 10Mbps)
RS-485/422
RECEIVER PROPAGATION
(FAST, 5Mbps)
MAX3160/2 TOC22
VY-VZ
2V/div
RO
2V/div
CL = 50pF
40ns/div
RS-485/422
DRIVER DISABLE/ENABLE
TO DRIVER OUTPUT
MAX3160/2 TOC24
DE48
2V/d
VY - V
2V/d
R = 50Ω
CL = 82pF
100ns/div
0
4
2
8
6
12
10
14
0 1.0 1.50.5 2.0 2.5 3.0 3.5
OUTPUT CURRENT vs. RECEIVER
OUTPUT HIGH VOLTAGE
MAX3160/2 TOC13
OUTPUT HIGH VOLTAGE (V)
OUTPUT CURRENT (mA)
Typical Operating Characteristics (continued)
(VCC = +3.3V, 250kbps data rate, 0.1µF capacitors, all RS-232 transmitters (RS-232 mode) loaded with 3kΩto ground, TA= +25°C,
unless otherwise noted.)
-1000
-800
-400
-600
0
200
-200
400
-20 -10 -5-15 0 5 101520
I-V OUTPUT IMPEDANCE CURVE
IN RS-232 SHUTDOWN MODE
MAX3160-A
VOLTS (V)
CURRENT (μA)
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 8www.maximintegrated.com
Pin Description
PIN
MAX3160 MAX3161 MAX3162 NAME FUNCTION
1 1 1 C1+ Positive Terminal of the Positive Flying Capacitor
222V
CC Positive Supply Voltage
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
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
— — 6 Z Inverting RS-485/422 Driver Output
— 6 — Z(B)
Inverting RS-485/422 Driver Output in Full-Duplex Mode
(and Inverting RS-485/422 Receiver Input in Half-Duplex
Mode)
6 — — Y(A)/T2OUT
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
— — 7 Y Noninverting RS-485/422 Driver Output
— 7 — Y(A)
Noninverting RS-485/422 Driver Output in Full-Duplex
Mode (and Noninverting RS-485/422 Receiver Input in
Half-Duplex Mode)
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 Active-Low Shutdown-Control Input. Drive low to shut
down transmitters and charge pump.
— — 10 R2OUT RS-232 Driver Output
10 12 14 FAST Select slew rate limiting for both RS-232 and RS-
485/422. Slew rate limits with a logic-level low.
— — 11 RO RS-485/422 Receiver Output
11 13 — RS485/RS232
Software-Programmable Pin Functionality. Operates as
RS-485/422 with a logic-level high; operates as RS-232
with a logic-level low.
——12RE485 RS-485/422 Receiver Enable. Logic-level low enables
RS-485/422 receivers.
12 14 — HDPLX
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
Maxim Integrated | 9www.maximintegrated.com
Pin Description (continued)
PIN
MAX3160 MAX3161 MAX3162 NAME FUNCTION
13 — — A/R2IN Noninverting RS-485/422 Receiver Input/RS-232
Receiver Input
14 — — B/R1IN Inverting RS-485/422 Receiver Input/RS-232 Receiver
Input
——15RE232 RS-232 Receiver Enable. Logic-level low enables RS-
232 receivers.
— 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
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 10www.maximintegrated.com
20
19
18
17
16
15
14
13
1
2
3
4
RS-232
OUTPUTS LOGIC
INPUTS
LOGIC
OUTPUTS RS-232
INPUTS
C1 C3
C2
C4
SHDN HDPLX
FAST RS485/RS232
5
6
7
8
129
V+
C2+
C2-
V-
C1-
GND
VCC
VCC
C1+
CHARGE
PUMP
T1
T2
R1
R2
CBYPASS
RS-232 MODE
1110
20
19
18
17
16
15
14
13
1
2
3
4
RS-485
OUTPUTS
LOGIC
INPUTS
LOGIC
OUTPUT
RS-485
INPUTS
SHDN
FAST RS485/RS232
5
6
7
8
V+
C2+
C2-
V-
C1-
GND
VCC
VCC
C1+
C1
CBYPASS
C2
C3
C4
12
11
9
10
CHARGE
PUMP
Z
Y
B
DE
A
RS-485 MODE
D
HALF/FULL
DUPLEX
R
R0
Functional Diagrams
MAX3160
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
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Functional Diagrams (continued)
C1
CBYPASS
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
VCC
VCC
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
VCC
VCC
C1+
14
13
11
12
CHARGE
PUMP
T1
T2
R1
R2
CBYPASS
RS-232 MODE
15
9
10
MAX3161
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
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TE232
RE485
R
B
A
Z
Y
RO
28
27
26
25
24
23
22
211
1
2
3
4
RS-485
OUTPUTS
RS-232
OUTPUT
RS-232
OUTPUT
LOGIC
OUTPUTS
RS-232
INPUTS
C1 C3
C2
C4
SHDN
FAST
5
6
7
8
V+
C2+
C2-
V-
C1-
GND
VCC
VCC C1+
16
15
13
14
CHARGE
PUMP
T1
T2
R1
R2
20
19
18
17
LOGIC
INPUTS
RS-485
INPUTS
9
10
11
12
DDE485
CBYPASS
Functional Diagrams (continued)
MAX3162
CL
CL
RDIFF
VOD
Z
3V
DE485
Y
DI
Figure 3. RS-485/422 Driver Timing Test Circuit
1k
CL
VCC
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
VOD
VOC
R
R
Z
Y
Test Circuits
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 13www.maximintegrated.com
Test Circuits (continued)
CL
VCC
OUTPUT
UNDER TEST
S1
S2
500Ω
Figure 4. RS-485/422 Driver Enable/Disable Timing Test Load
DI
3V
0
Z
Y
VO
0
-VO
VO
1.5V
tDPLH
1/2 VO
10%
TDR
90% 90%
tDPHL
1.5V
1/2 VO
10%
TDF
VDIFF = Vy - Vz
VDIFF
tDSKEW = | tDPLH - tDPHL |
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0
Y, Z
VOL
Y, Z
0
1.5V 1.5V
VOL +0.5V
VOH -0.5V
2.3V
2.3V
tDZL tDLZ
tDZH tDHZ
DE485
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0
VCC
RO
RO
0
1.5V 1.5V
VOL + 0.5V
VOH - 0.5V
1.5V
1.5V
tRZL tRLZ
tRZH tRHZ
RE485
Figure 5. RS-485/422 Driver Propagation Delays
Figure 6. RS-485/422 Driver Enable and Disable Times
VOH
VOL
A
B
1V
-1V
VCC/2 VCC/2
OUTPUT
INPUT
RO
tRPLH
tRPHL
VID
CL
A
B
RRO
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
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 14www.maximintegrated.com
Detailed Description
The MAX3160/MAX3161/MAX3162 3V/5V, multiprotocol
transceivers can be pin configured in a number of RS-
232 and RS-485/422 interface combinations. These cir-
cuit configurations are ideal for the design of RS-232 to
RS-485 converters, multiprotocol buses, or any applica-
tion that requires both RS-232 and RS-485 transceivers.
The slew rate of these devices is on-the-fly pin pro-
grammable, 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 (avail-
able 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 prima-
ry 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 trans-
ceivers, and common digital I/O pins. The MAX3160 is
optimized for multiprotocol operation on a single inter-
face 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 trans-
ceivers, 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 trans-
ceivers, 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 RS-
232 mode, capable of RS-232-compliant communica-
tion. 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 5kΩfor RS-232
operation.
MAX3161
The MAX3161 is a 2TX/2RX RS-232 transceiver in RS-
232 mode or a single RS-485/422 transceiver in RS-485
mode. When in RS-485 mode, the unused RS-232 trans-
mitter 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 5kΩto 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 dri-
vers, receivers, and transmitters can be enabled or dis-
abled by pin configuration. All outputs are high-Z when
not activated. RS-232 receiver inputs are 5kΩwhen
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 lim-
iting of the RS-232 transmitters and the RS-485/422 dri-
vers. 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 RS-
485/422 data rates up to 10Mbps are possible when
FAST is asserted. FAST can be changed during opera-
tion 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 inter-
nally 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 sup-
ply current is reduced to 1µA. The RS-232 receiver out-
puts remain active if in RS-232 mode. The charge-
pump 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 volt-
ages (VCC) over the 3.0V to 5.5V range. The charge
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 15www.maximintegrated.com
pumps operate in a discontinuous mode: if the magni-
tude of either output voltage is less than 5.5V, the
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 capaci-
tor (C1, C2) and a reservoir capacitor (C3, C4) to gen-
erate the V+ and V- supplies (see
Functional
Diagrams).
RS-485/422 Transceivers
The MAX3160/MAX3161/MAX3162 RS-485/422 trans-
ceivers 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 termi-
nated transmission line with all drivers disabled (see
Fail-Safe
). The MAX3160/MAX3161/MAX3162 also fea-
ture pin-selectable reduced slew-rate drivers that mini-
mize 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 dissi-
pation. Half-duplex communication is enabled by dri-
ving HDPLX high.
Fail-Safe
The MAX3160/MAX3161/MAX3162 guarantee a logic-
high 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 volt-
age (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 com-
plies 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 trans-
mitters are guaranteed at a 250kbps data rate in slew-
rate limited mode (FAST = GND) with worst-case loads
of 3kΩin 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 out-
put 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 5kΩresistors, forcing the outputs
to a logic high. The MAX3162 has transmitter and receiv-
er enable pins that allow its outputs to be three-stated.
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 capac-
itors for 3.3V operation. For other supply voltages, see
Table 13 for required capacitor values. Do not use val-
ues smaller than those listed in Table 13. Increasing the
capacitor values reduces ripple on the transmitter out-
puts and slightly reduces power consumption. C2, C3,
and C4 can be changed without changing C1’s value.
However, do not increase C1 without also increas-
ing the values of C2, C3, C4, and CBYPASS to main-
tain 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 VCC to 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 trans-
mitter outputs are shown going to opposite RS-232 lev-
els (one transmitter input is high, the other is low). Each
transmitter is loaded with 3kΩin parallel with 1000pF.
The transmitter outputs display no ringing or undesir-
able 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
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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 loop-
back 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 receiv-
er input impedance (48kΩ), allowing up to 128 trans-
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
INPUTS OUTPUTS
SHDN RS485
RR
RRSS
SS22
2233
3322
22
DI/T1IN,
DE485/T2IN
Z(B)/T1OUT,
Y(A)/T2OUT
0 X X 1/8 Unit Load
10 0 1
10 1 0
1 1 X RS-485 Mode
Table 1. MAX3160
INPUTS OUTPUTS
SHDN RS-485/
RS-232
DI/T1IN,
DE485/T2IN
T1OUT,
T2OUT
0 X X High-Z
10 0 1
10 1 0
1 1 X High-Z
Table 2. MAX3161
INPUTS OUTPUTS
SHDN TE232 T1IN,T2IN T1OUT,
T2OUT
0 X X High-Z
X 0 X High-Z
11 0 1
11 1 0
Table 3. MAX3162
INPUTS OUTPUTS
SHDN RS-485/
RR
RRSS
SS--
--22
2233
3322
22
B/R1IN,
A/R2IN
R1OUT,
RO/R2OUT
X0 0 1
X0 1 0
X 0 Inputs Open 1
X1 X
R1OUT
High-Z,
RO/R2OUT in
RS-485 mode
Table 4. MAX3160
INPUTS OUTPUTS
SHDN RS-485/
RR
RRSS
SS--
--22
2233
3322
22 R1IN, R2IN R1OUT,
RO/R2OUT
X0 0 1
X0 1 0
X 0 Inputs Open 1
X1 X
R1OUT
High-Z,
RO/R2OUT in
RS-485 mode
Table 5. MAX3161
RS-232 Transmitters
INPUTS OUTPUTS
SHDN RE232 R1IN, R2IN R1OUT,
R2OUT
X 1 X High-Z
X0 0 1
X0 1 0
X 0 Inputs open 1
Table 6. MAX3162
RS-232 Receivers
Truth Tables
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
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INPUTS OUTPUTS
SHDN RS485/RR
RRSS
SS22
2233
3322
22 DE485/T2IN DI/T1IN Z(B)/T1OUT Y(A)/T2OUT
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
Table 7. MAX3160
INPUTS OUTPUTS
SHDN RS485/RR
RRSS
SS22
2233
3322
22 DE485/T2IN DI/T1IN Z(B) Y(A)
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
Table 8. MAX3161
INPUTS OUTPUTS
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
Table 9. MAX3162
INPUTS OUTPUT
RS485/RS232 SHDN HDPLX A - B* Y - Z* RO/R2OUT
1 0 X X X High-Z Up to VCC
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
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
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 18www.maximintegrated.com
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 out-
puts are 1/8-unit load when disabled This impedance
may be reduced if the D1 pin is toggled at a high fre-
quency. With no power applied (VCC = GND), the RS-
485 transmitter output impedances typically go to 1/2-
unit 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 con-
tention. The first, a foldback current limit on the output
stage, provides immediate protection against short cir-
cuits over the whole common-mode voltage range (see
Typical Operating Characteristics
). The second, a ther-
mal 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 ter-
minated cables. Operation in slew-rate limited mode
reduces the amplitudes of high-frequency harmonics.
SUPPLY VOLTAGE
(V) C1 (µF) C2, C3, C4, CBYPASS
(µF)
+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
Table 13. Required Minimum
Capacitance Values
INPUTS OUTPUT
RS485/RS232 SHDN HDPLX A - B Y(A) - Z(B) RO/R2OUT
1 0 X X X High-Z up to VCC
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
Table 11. MAX3161
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
Table 12. MAX3162
Truth Tables (continued)
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
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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 RS-
232/RS-485 protocol translator. The direction of transla-
tion 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 trans-
mitted as an RS-232 signal on T1OUT.
Multiprotocol Bus
The
Typical Operating Circuit
shows a standard appli-
cation 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 shut-
down functions, enable lines, and the duplex of the
MAX3160. Data is transmitted to the MAX3100 UART
MAX 3160-2 FIG10
T1OUT
2V/div
SHDN
5V/division
T2OUT
2V/div
GND
40
μ
s/div
Figure 10. MAX3160 RS-232 Transmitter Outputs When Exiting
Shutdown
MAX 3160-2 FIG12
TOUT
5V/div
ROUT
TIN
1
μ
s/div
Figure 12. RS-232 Loopback Test Result at 250kbps, FAST =
Low
MAX 3160-2 FIG13
TIN
TOUT
5V/div
ROUT
200ns/div
Figure 13. RS-232 Loopback Test Result at 1000kbps, FAST =
High
MAX3160
MAX3161
MAX3162
5k
R_ IN
R_ OUT
C2-
C2+
C1-
C1+
V-
V+
VCC
C4
C3
C1
C2
VCC
CBYPASS
SHDN
T_ OUT
T_ IN
GND
VCC
1000pF
Figure 11. Loopback Test Circuit
SPI is a trademark of Motorola, Inc.
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
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through an SPI™ port. The UART asynchronously
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 con-
figured 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 mul-
tidrop RS-485 interface. The MAX3100 UART asynchro-
nously transfers data through the MAX3161 to the
pin-selected RS-232 or RS-485 protocol.
A
B
Z
D DATA OUT
DATA IN
R
DI
DE485
RE485
RO
Y
120Ω
120Ω
NOTE: RE485 ON MAX3162 ONLY
MAX3160
MAX3161
MAX3162
Figure 14. RS-485 Line Repeater
MAX3162
R1OUT
RO
RE485
DE485
A
B
Z
Y
V-
R1IN
RE232
TE232
FAST
V+
T1OUT
C2-
C2+
C1-
C1+
VCC
T1IN
R2OUT
DI
R2IN
GND
27
26
13
5
10
23
19
20
15
16
14
28 25
7
6
18
17
22
12
9
11
24
3
1
C1
100nF
C2
100nF
RCV
TX
RTS
C3
100nF
C4
100nF
2
3.3V
CBYPASS
100nF
SHDN
4
Figure 15. Protocol Translator
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 21www.maximintegrated.com
+
TX
VCC HDPLX
DI/T1IN T1OUT
R1OUT R1IN
DE/T2IN
GND FAST SHDN
T2OUT
RO/R2OUT R2IN
RX
RTS
CTS
13
RS-485/RS-232
12
11
10
19 8
10 17
918
Y(A) RS-485
Z(B)
7
6
1
412
20 5
RJ45
DB9
RS-232
SHDN
μP
MAX3100
214
UART
MAX3161
SPI
Typical Application Circuit
EIA/TIA-232
STANDARD
CONNECTOR
PIN
MAX3160
MAX3161
MAX3162
PIN NUMBER
EQUIVALENT MAX3160 MAX3161 MAX3162
FUNCTION
(as seen by DTE)
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 Request to Send (= DTE
ready)
CTS 8 R1IN 14 18 20 Clear to Send (= DCE ready)
RI 9 Ring Indicator
Table 14. Cable Connections Commonly Used for EIA/TIA-232 and
V.24 Asynchronous Interfaces
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
Maxim Integrated | 22www.maximintegrated.com
Pin Configurations
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
V+
C2+
C2-
V-GND
C1-
VCC
C1+
+
TOP VIEW
DI/T1IN
DE485/T2IN
B/R1IN
A/R2INRO/R2OUT
R1OUT
Y(A)/T2OUT
Z(B)/T1OUT
12
11
9
10
HDPLX
FAST
MAX3160
20-PIN SSOP
RS-485/RS-232
24
23
22
21
20
19
18
17
1
2
3
4
5
6
7
8
V+
C2+
C2-
V-GND
C1-
VCC
C1+
DI/T1IN
DE485/T2IN
R1IN
R2INT2OUT
Y(A)
Z(B)
T1OUT
16
15
14
13
9
10
11
12
B
A
HDPLX
RS-485/RS-232FAST
RO/R2OUT
R1OUT
24-PIN SSOP
MAX3161
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
V+
C2+
C2-
V-
T1IN
DI
RE232
DE485
T2IN
R1IN
R2IN
B
A
TE232
FAST
SHDN
RE485
RO
R2OUT
R1OUT
T2OUT
Y
Z
T1OUT
GND
C1-
VCC
C1+
28-PIN SSOP
MAX3162
SHDN
SHDN
++
PART DUAL-MODE
FLOW-
THROUGH
PIN-OUT
RS-485
INPUT UNIT
LOADS
MAX3160 No Yes 1/4
MAX3161 No No 1/8
MAX3162 Yes Yes 1/8
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 (foot-
prints), go to www.maximintegrated.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.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and
max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. © 2015 Maxim Integrated Products, Inc. | 23
MAX3160/MAX3161/MAX3162 +3.0V to+5.5V, 1µA, RS-232/
RS-485/422 Multiprotocol Transceivers
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
Corrected the “Continuous Power Dissipation” specifications under the Absolute
Maximum Ratings. 2
Changed pin labels in the Functional Diagrams. 11
2 12/09
Deleted “TRANSISTOR COUNT: 1580” and added “PROCESS: BiCMOS” to the Chip
Information. 22
3 5/15 Updated the General Description and Benefits and Features sections 1
