Maxim MAX3491EEPD, MAX3491ECSD, MAX3490EESA, MAX3490EEPA, MAX3490ECSA Datasheet

General Description

Devices in the MAX3483E family (MAX3483E/MAX3485E/
MAX3486E/MAX3488E/MAX3490E/MAX3491E) are
±15kV ESD-protected, +3.3V, low-power transceivers for
RS-485 and RS-422 communications. Each device con­tains one driver and one receiver. The MAX3483E and
MAX3488E feature slew-rate-limited drivers that minimize
EMI and reduce reflections caused by improperly termi­nated cables, allowing error-free data transmission at
data rates up to 250kbps. The partially slew-rate-limited
MAX3486E transmits up to 2.5Mbps. The MAX3485E,
MAX3490E, and MAX3491E transmit at up to 12Mbps.

All devices feature enhanced electrostatic discharge
(ESD) protection. All transmitter outputs and receiver
inputs are protected to ±15kV using IEC 1000-4-2 Air­Gap Discharge, ±8kV using IEC 1000-4-2 Contact
Discharge, and ±15kV using the Human Body Model.

Drivers are short-circuit current limited and are protect­ed against excessive power dissipation by thermal
shutdown circuitry that places the driver outputs into a
high-impedance state. The receiver input has a fail-safe
feature that guarantees a logic-high output if both
inputs are open circuit.

The MAX3488E, MAX3490E, and MAX3491E feature
full-duplex communication, while the MAX3483E,
MAX3485E, and MAX3486E are designed for half­duplex communication.

Applications

Telecommunications
Industrial-Control Local Area Networks
Transceivers for EMI-Sensitive Applications
Integrated Services Digital Networks
Packet Switching

Features

♦ ESD Protection for RS-485 I/O Pins

±15kV—Human Body Model
±8kV—IEC 1000-4-2, Contact Discharge
±15kV—IEC 1000-4-2, Air-Gap Discharge

♦ Operate from a Single +3.3V Supply—

No Charge Pump Required

♦ Interoperable with +5V Logic
♦ Guaranteed 12Mbps Data Rate

(MAX3485E/MAX3490E/MAX3491E)

♦ Slew-Rate Limited for Errorless Data Transmission

(MAX3483E/MAX3488E)

♦ 2nA Low-Current Shutdown Mode

(MAX3483E/MAX3485E/MAX3486E/MAX3491E)

♦ -7V to +12V Common-Mode Input Voltage Range
♦ Full-Duplex and Half-Duplex Versions Available
♦ Industry-Standard 75176 Pinout

(MAX3483E/MAX3485E/MAX3486E)

♦ Current-Limiting and Thermal Shutdown for

Driver Overload Protection

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and

Slew-Rate-Limited True RS-485/RS-422 Transceivers

________________________________________________________________

Maxim Integrated Products

1

19-1474; Rev 0; 4/99

PART

MAX3483ECSA

MAX3483ECPA 0°C to +70°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

8 SO
8 Plastic DIP

PART

NUMBER

GUARANTEED

DATA RATE

(Mbps)

SUPPLY

VOLTAGE

(V)

HALF/FULL

DUPLEX

SLEW-RATE

LIMITED

DRIVER/

RECEIVER

ENABLE

SHUTDOWN

CURRENT

(nA)

PIN

COUNT

MAX3483E 0.25 Half Yes Yes 2 8
MAX3485E 12 Half No Yes 2 8
MAX3486E 2.5 Half Yes Yes 2 8
MAX3488E 0.25 Full Yes No — 8
MAX3490E 12 Full No No — 8
MAX3491E 12

3.0 to 3.6

Full No Yes 2 14

Selector Guide

MAX3483EESA
MAX3483EEPA -40°C to +85°C

-40°C to +85°C 8 SO
8 Plastic DIP

MAX3485ECSA
MAX3485ECPA 0°C to +70°C

0°C to +70°C 8 SO

8 Plastic DIP

MAX3485EESA
MAX3485EEPA -40°C to +85°C

-40°C to +85°C 8 SO
8 Plastic DIP

Ordering Information

Ordering Information continued at end of data sheet.

±15kV

ESD

PROTECTION

Yes
Yes
Yes
Yes
Yes
Yes

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and
Slew-Rate-Limited True RS-485/RS-422 Transceivers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

DC ELECTRICAL CHARACTERISTICS

(VCC= +3.3V ±0.3V, TA= 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.

Supply Voltage (VCC).............................................................+7V

Control Input Voltage (

RE, DE).................................-0.3V to +7V

Driver Input Voltage (DI)...........................................-0.3V to +7V

Driver Output Voltage (A, B, Y, Z).......................-7.5V to +12.5V

Receiver Input Voltage (A, B)..............................-7.5V to +12.5V

Receiver Output Voltage (RO)....................-0.3V to (V

CC

+ 0.3V)

Continuous Power Dissipation (T

A

= +70°C)

8-Pin SO (derate 5.88mW/°C above +70°C)..................471mW

8-Pin Plastic DIP (derate 9.09mW/°C above +70°C) .....727mW

14-Pin SO (derate 8.33mW/°C above +70°C)................667mW

14-Pin Plastic DIP (derate 10mW/°C above +70°C) ......800mW

Operating Temperature Ranges

MAX34_ _ EC_ _ ...................................................0°C to +70°C

MAX34_ _ EE_ _.................................................-40°C to +85°C

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

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

DE = 0,
V

CC

= 0 or 3.6V

DE = 0, RE = VCC,
V

CC

= 0 or 3.6V, MAX3491E

DE = 0, RE = 0,
V

CC

= 0 or 3.6V, MAX3491E

kΩ12R

IN

Receiver Input Resistance

µA±1I

OZR

Three-State (High-Impedance)
Output Current at Receiver

V0.4V

OL

Receiver Output Low Voltage

VVCC- 0.4V

OH

Receiver Output High Voltage

mV50∆V

TH

Receiver Input Hysteresis

V-0.2 0.2V

TH

Receiver Differential
Threshold Voltage

µA

-1

I

O

Output Leakage (Y, Z)
in Shutdown Mode

1

µA

-20

I

O

Output Leakage (Y, Z)

V0.2∆V

OD

Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States
(Note 1)

V

1.5

V

OD

2.0

Differential Driver Output

20

mA

-0.8

I

IN2

Input Current (A, B)

1.0

µA±2I

IN1

Logic Input Current

V3V

OC

Driver Common-Mode Output
Voltage

V0.2∆V

OC

Change in Magnitude of
Common-Mode Output Voltage
(Note 1)

V2.0V

IH

Input High Voltage

V0.8V

IL

Input Low Voltage

UNITS

MIN TYP MAX

SYMBOLPARAMETER

RL= 54Ω or 100Ω, Figure 4

-7V ≤ VCM≤ 12V

RL= 54Ω (RS-485), Figure 4

VCC= 3.6V, 0 ≤ V

OUT

≤ V

CC

RL= 100Ω (RS-422), Figure 4

I

OUT

= 2.5mA, VID= 200mV, Figure 6

I

OUT

= -1.5mA, VID= 200mV, Figure 6

VCM= 0

V

OUT

= 12V

VIN= -7V

-7V ≤ VCM≤ 12V

V

OUT

= -7V

VIN= 12V

DE, DI, RE

RL= 54Ω or 100Ω, Figure 4

RL= 54Ω or 100Ω, Figure 4

DE, DI, RE

V

OUT

= 12V

DE, DI, RE

V

OUT

= -7V

CONDITIONS

RL= 60Ω (RS-485), VCC= 3.3V, Figure 5

1.5

mA

1.1 2.2

I

CC

Supply Current

No load,
DI = 0 or V

CC

DE = VCC, RE = 0 or V

CC

DE = 0, RE = 0

0.95 1.9

V3.0 3.6V

CC

Supply Voltage Range

µA0.002 1I

SHDN

Supply Current in Shutdown Mode

DE = 0, RE = VCC, DI = VCCor 0

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and

Slew-Rate-Limited True RS-485/RS-422 Transceivers

_______________________________________________________________________________________ 3

mA

-250

I

OSD

250

Driver Short-Circuit Output Current

mA±8 ±60I

OSR

Receiver Short-Circuit Output Current

UNITSMIN TYP MAXSYMBOLPARAMETER

V

OUT

= -7V

V

OUT

= 12V

0 ≤ VRO≤ V

CC

CONDITIONS

DC ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V ±0.3V, TA= T

MIN

to T

MAX

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

ns72335t

PLH

Driver Propagation Delay, Low-to-High Level

ns31125t

TD

Mbps12 15Maximum Data Rate

Driver Differential Output Transition Time

ns650 900t

PSH

Driver-Output Enable Time from Shutdown to High Level

ns650 900t

PSL

Driver-Output Enable Time from Shutdown to Low Level

ns35 80t

PHZ

Driver-Output Disable Time from High Level

ns72335t

PHL

Driver Propagation Delay, High-to-Low Level

ns-1.4 ±8t

PDS

|

t

PLH

- t

PHL|

Driver Propagation-Delay Skew (Note 2)

ns42 90t

PZL

Driver-Output Enable Time to Low Level

ns42 90t

PZH

Driver-Output Enable Time to High Level

UNITSMIN TYP MAXSYMBOLPARAMETER

RL= 27Ω, Figure 8

RL= 60Ω, Figure 7

RL= 110Ω, Figure 9

RL= 110Ω, Figure 10

RL= 110Ω, Figure 9

RL= 27Ω, Figure 8
RL= 27Ω, Figure 8

RL= 110Ω, Figure 10
RL= 110Ω, Figure 9

CONDITIONS

DRIVER SWITCHING CHARACTERISTICS—MAX3485E/MAX3490E/MAX3491E

(VCC= +3.3V, TA= +25°C.)

ns35 80t

PLZ

Driver-Output Disable Time from Low Level RL= 110Ω, Figure 10

DRIVER SWITCHING CHARACTERISTICS—MAX3486E

(VCC= +3.3V, TA= +25°C.)

ns40 80t

PLZ

Driver-Output Disable Time from Low Level RL= 110Ω, Figure 10

ns20 42 75t

PLH

Driver Propagation Delay, Low-to-High Level

ns15 28 60t

TD

Mbps2.5Maximum Data Rate

Driver Differential Output Transition Time

ns700 1000t

PSH

Driver-Output Enable Time from Shutdown to High Level

ns700 1000t

PSL

Driver-Output Enable Time from Shutdown to Low Level

ns40 80t

PHZ

Driver-Output Disable Time from High Level

ns20 42 75t

PHL

Driver Propagation Delay, High-to-Low Level

ns-6 ±12t

PDS

|

t

PLH

- t

PHL|

Driver Propagation-Delay Skew (Note 2)

ns52 100t

PZH

Driver-Output Enable Time to High Level

UNITSMIN TYP MAXSYMBOLPARAMETER

RL= 27Ω, Figure 8

RL= 60Ω, Figure 7

RL= 110Ω, Figure 9

RL= 110Ω, Figure 10

RL= 110Ω, Figure 9

RL= 27Ω, Figure 8
RL= 27Ω, Figure 8

RL= 110Ω, Figure 9

CONDITIONS

±15IEC 1000-4-2 Air Discharge

±6

IEC 1000-4-2 Contact Discharge
(MAX3490E, MAX3488E)*

±8

IEC 1000-4-2 Contact Discharge
(MAX3483E, MAX3485E,
MAX3486E, MAX3491E)

ns12235t

DD

Driver Differential Output Delay RL= 60Ω, Figure 7

DRIVER-OUTPUT ENABLE/DISABLE TIMES (MAX3485E/MAX3491E only)

ns20 42 70t

DD

Driver Differential Output Delay RL= 60Ω, Figure 7

ESD Protection for Y, Z, A, B

±15Human Body Model

kV

*

MAX3488E and MAX3491E will be compliant to ±8kV per IEC 1000-4-2 Contact Discharge by September 1999.

ns52 100t

PZL

Driver-Output Enable Time to Low Level RL= 110Ω, Figure 10

DRIVER-OUTPUT ENABLE/DISABLE TIMES

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and
Slew-Rate-Limited True RS-485/RS-422 Transceivers

4 _______________________________________________________________________________________

DRIVER SWITCHING CHARACTERISTICS—MAX3483E/MAX3488E

(VCC= +3.3V, TA= +25°C.)

ns50 80t

PLZ

Driver-Output Disable Time from Low Level RL= 110Ω, Figure 10

ns700 930 1500t

PLH

Driver Propagation Delay, Low-to-High Level

ns400 740 1200t

TD

kbps250Maximum Data Rate

Driver Differential Output Transition Time

µs2.2 3.0t

PSH

Driver-Output Enable Time from Shutdown to High Level

µs1.9 2.7t

PSL

Driver-Output Enable Time from Shutdown to Low Level

ns50 80t

PHZ

Driver-Output Disable Time from High Level

ns700 930 1500t

PHL

Driver Propagation Delay, High-to-Low Level

ns±50t

PDS

|

t

PLH

- t

PHL|

Driver Propagation-Delay Skew (Note 2)

ns600 800t

PZH

Driver-Output Enable Time to High Level

UNITSMIN TYP MAXSYMBOLPARAMETER

RL= 27Ω, Figure 8

RL= 60Ω, Figure 7

RL= 110Ω, Figure 9

RL= 110Ω, Figure 10

RL= 110Ω, Figure 9

RL= 27Ω, Figure 8
RL= 27Ω, Figure 8

RL= 110Ω, Figure 9

CONDITIONS

RECEIVER SWITCHING CHARACTERISTICS

(VCC= +3.3V, TA= +25°C.)

ns25 45t

PRLZ

Receiver-Output Disable
Time from Low Level

CL= 15pF, Figure 12,
MAX3483E/85E/86E/91E only

ns

25 62 90

ns80 190 300t

SHDN

Time to Shutdown

ns720 1400t

PRSH

Receiver-Output Enable Time
from Shutdown to High Level

ns720 1400t

PRSL

Receiver-Output Enable Time
from Shutdown to Low Level

ns25 45t

PRHZ

Receiver-Output Disable
Time from High Level

ns

25 62 90

ns

6±10

ns25 50t

PRZL

Receiver-Output Enable Time
to Low Level

ns25 50t

PRZH

Receiver-Output Enable Time
to High Level

UNITSMIN TYP MAXSYMBOLPARAMETER

VID= 0 to 3.0V, CL= 15pF, Figure 11

MAX3483E/MAX3485E/MAX3486E/MAX3491E
only (Note 3)

CL= 15pF, Figure 12,
MAX3483E/85E/86E/91E only

CL= 15pF, Figure 12,
MAX3483E/85E/86E/91E only

CL= 15pF, Figure 12,
MAX3483E/85E/86E/91E only

VID= 0 to 3.0V, CL= 15pF, Figure 11

VID= 0 to 3.0V, CL= 15pF, Figure 11

CL= 15pF, Figure 12,
MAX3483E/85E/86E/91E only

CL= 15pF, Figure 12,
MAX3483E/85E/86E/91E only

CONDITIONS

25 75 120

t

RPLH

Receiver Propagation Delay,
Low-to-High Level

MAX3483E/MAX3488E

25 75 120

t

RPHL

Receiver Propagation Delay,
High-to-Low Level

MAX3483E/MAX3488E

12 ±20

t

RPDS

|

t

PLH

- t

PHL|

Receiver

Propagation-Delay Skew

MAX3483E/MAX3488E

Note 1: ∆VODand ∆VOCare the changes in VODand VOC, respectively, when the DI input changes state.
Note 2: Measured on

|t

PLH

(Y) - t

PHL

(Y)| and |t

PLH

(Z) - t

PHL

(Z)|.

Note 3: The transceivers are put into shutdown by bringing RE high and DE low. If the inputs are in this state for less than 80ns, the

devices are guaranteed not to enter shutdown. If the inputs are in this state for at least 300ns, the devices are guaranteed
to have entered shutdown. See

Low-Power Shutdown Mode

section.

ns900 1300t

PZL

Driver-Output Enable Time to Low Level RL= 110Ω, Figure 10

ns600 900 1400t

DD

Driver Differential Output Delay RL= 60Ω, Figure 7

DRIVER-OUTPUT ENABLE/DISABLE TIMES (MAX3483E only)

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and

Slew-Rate-Limited True RS-485/RS-422 Transceivers

_______________________________________________________________________________________

5

Typical Operating Characteristics

(VCC= +3.3V, TA= +25°C, unless otherwise noted.)

25

20

15

10

5

0

0 0.5 1.0 1.5 2.0 2.5 3.53.0

OUTPUT CURRENT vs.

RECEIVER OUTPUT LOW VOLTAGE

MAX3483E-01

OUTPUT LOW VOLTAGE (V)

OUTPUT CURRENT (mA)

-20

-18

-16

-14

-12

-10

-8

-6

-4

-2
0

0 0.5 1.0 1.5 2.0 2.5 3.53.0

OUTPUT CURRENT vs.

RECEIVER OUTPUT HIGH VOLTAGE

MAX3483E-02

OUTPUT HIGH VOLTAGE (V)

OUTPUT CURRENT (mA)

3.00

3.05

3.10

3.15

3.20

3.25

3.30

-40 -20 0 20 40 60 10080

RECEIVER OUTPUT HIGH VOLTAGE

vs. TEMPERATURE

MAX3483E-03

TEMPERATURE (°C)

OUTPUT HIGH VOLTAGE (V)

IRO = 1.5mA

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

-40 -20 0 20 40 60 10080

RECEIVER OUTPUT LOW VOLTAGE

vs. TEMPERATURE

MAX3483E-04

TEMPERATURE (°C)

OUTPUT LOW VOLTAGE (V)

IRO = 2.5mA

25

0

50

75

100

125

150

175

0246 81012

OUTPUT CURRENT vs.

DRIVER OUTPUT LOW VOLTAGE

MAX3483E-07

OUTPUT LOW VOLTAGE (V)

OUTPUT CURRENT (mA)

100

90
80
70
60
50
40
30
20

10

0

0 0.5 1.0 1.5 2.0 2.5 3.53.0

DRIVER OUTPUT CURRENT vs.

DIFFERENTIAL OUTPUT VOLTAGE

MAX3483E-05

DIFFERENTIAL OUTPUT VOLTAGE (V)

OUTPUT CURRENT (mA)

1.6

1.7

1.8

1.9

2.0

2.1

2.2

2.3

2.4

2.6

2.5

-40 -20 0 20 40 60 10080

DRIVER DIFFERENTIAL OUTPUT

VOLTAGE vs. TEMPERATURE

MAX3483E-06

TEMPERATURE (°C)

DIFFERENTIAL OUTPUT VOLTAGE (V)

R = 54Ω

0

-100

-80

-60

-40

-20

543210

-7 -6 -3-4-5 -2 -1

OUTPUT CURRENT vs.

DRIVER OUTPUT HIGH VOLTAGE

MAX3483E-08

OUTPUT HIGH VOLTAGE (V)

OUTPUT CURRENT (mA)

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and
Slew-Rate-Limited True RS-485/RS-422 Transceivers

6 _______________________________________________________________________________________

0.8

0.7

0.9

1.0

1.1

1.2

-40 -20 0 20 40 60 10080

SUPPLY CURRENT

vs. TEMPERATURE

MAX3483E-09

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

X = DON’T CARE

DE = VCC, RE = X

DE = 0, RE = 0

Typical Operating Characteristics (continued)

(VCC= +3.3V, TA= +25°C, unless otherwise noted.)

0

10

20

30

40

50

60

70

80

100

90

-40 -20 0 20 40 60 10080

SHUTDOWN CURRENT

vs. TEMPERATURE

MAX3483E-10

TEMPERATURE (°C)

SHUTDOWN CURRENT (nA)

Pin Description

—

—

3
4

5
6

—

8

—

7
1

—

MAX3483E
MAX3485E
MAX3486E

21

2

3

4

5
—
—

6
—

7
—

8
—

2

Receiver Output. If A > B by 200mV, RO will be high; if A < B by 200mV,
RO will be low.

3

Receiver Output Enable. RO is enabled when RE is low; RO is high imped­ance when RE is high. If RE is high and DE is low, the device will enter a
low-power shutdown mode.

4

Driver Output Enable. The driver outputs are enabled by bringing DE high.
They are high impedance when DE is low. If RE is high and DE is low, the
device will enter a low-power shutdown mode. If the driver outputs are
enabled, the parts function as line drivers. While they are high impedance,
they function as line receivers if RE is low.

5

Driver Input. A low on DI forces output Y low and output Z high. Similarly, a
high on DI forces output Y high and output Z low.

6, 7 Ground

9 Noninverting Driver Output
10 Inverting Driver Output
— Noninverting Receiver Input and Noninverting Driver Output
12 Noninverting Receiver Input

RO

RE

DE

DI

GND

Y
Z
A

A
— B Inverting Receiver Input and Inverting Driver Output
11 B Inverting Receiver Input

13, 14 V

CC

Positive Supply: 3.0V ≤ VCC≤ 3.6V. Do not operate device with VCC> 3.6V.

1, 8 N.C. No Connection. Not internally connected.

MAX3488E
MAX3490E

PIN

FUNCTION

MAX3491E

FUNCTION

NAME

NAME

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and

Slew-Rate-Limited True RS-485/RS-422 Transceivers

_______________________________________________________________________________________ 7

MAX3483E
MAX3485E
MAX3486E

TOP VIEW

NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.

1
2
3
4

8

5

V

CC

GND

DI

DE

RE

RO

R

D

Rt

Rt

7
6

D

R

DE

RE

DI

RO

A

B

1
2
3
4

8
7
6
5

V

CC

B
A
GND

DI

DE

RE

RO

SO/DIP

R

D

B

A

Figure 2. MAX3488E/MAX3490E Pin Configuration and Typical Operating Circuit

Figure 3. MAX3491E Pin Configuration and Typical Operating Circuit

Figure 1. MAX3483E/MAX3485E/MAX3486E Pin Configuration and Typical Operating Circuit

V

TOP VIEW

V

GND

V

CC

1

MAX3488E
MAX3490E

Y

3

A

1

CC

RO

DI

R
2
3
4

D

8

B

7
6

Z

Y

5

DI

RO

DR

2

5
6

Z

8

A

R

Rt

7

B

Rt

SO/DIP

4
GND

CC

D

GND

RO

DI

TOP VIEW

14

V

CC

V

13

CC

12

A
B

11
10

Z
Y

9
8

N.C.

N.C.

5

DI

2

RO

1, 8

N.C.

GND
GND

1

RO

2
3

RE

DE

4
5

DI

6
7

R

D

SO/DIP

DE V

CC

13, 144

9

Y

D

3 6, 7

10

Z

12

A

RD

11

B

RE GND

MAX3491E

Rt

VCCRE

Rt

R

GND DE

RO

DI

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and
Slew-Rate-Limited True RS-485/RS-422 Transceivers

8 _______________________________________________________________________________________

V

CC

D

V

OD

V

OC

2

R

L

2

R

L

Figure 4. Driver VODand V

OC

Figure 7. Driver Differential Output Delay and Transition Times

Figure 6. Receiver V

OH

and V

OL

Figure 5. Driver VODwith Varying Common-Mode Voltage

375Ω

VCM =

V

D

V

CC

OD

R

L

375Ω

-7V to +12V

V

ID

0

GENERATOR

(NOTE 4)

R

50Ω

V

OL

C

L

D

V

CC

C

L

V

OH

I

OL

(+)

R

L

60Ω

C

= 15pF (NOTE 5)

L

I

OH

(-)

3V

IN

OUT

=

OUT

1.5V

t

DD

90%

50%

10%

t

TD

1.5V

90%

0

t

DD

≈ 2.0V

50%

10%

t

TD

≈ -2.0V

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and

Slew-Rate-Limited True RS-485/RS-422 Transceivers

_______________________________________________________________________________________ 9

V

CC

V

OM

3V

0V

V

OH

V

OM

V

OM

V

OM

V

OM

V

OL

V

OH

V

OL

50Ω

R

L

= 27Ω

CL = 15pF
(NOTE 5)

GENERATOR

(NOTE 4)

D

t

PLH

1.5V

Y

OUT

Z

OUT

OUT

S1

IN

1.5V

≈ 1.5V

t

PHL

t

PHL

t

PLH

VOH + V

OL

2

V

OM

=

Figure 8. Driver Propagation Times

Figure 9. Driver Enable and Disable Times (t

PZH

, t

PSH

, t

PHZ

)

Figure 10. Driver Enable and Disable Times (t

PZL

, t

PSL

, t

PLZ

)

S1

D0 OR 3V

C

= 50pF

L

GENERATOR

(NOTE 4)

(NOTE 5)

50Ω

S1

0 OR 3V

GENERATOR

(NOTE 4)

D

= 50pF

C

L

(NOTE 5)

50Ω

V

OM

=

VOH + V

2

V

CC

OL

≈ 1.5V

RL = 110Ω

= 110Ω

R

L

OUT

OUT

3V

IN

OUT

IN

OUT

t

PSL

1.5V

t

PZH

1.5V

V

OM

V

OM

1.5V
0

t

PHZ

V

OH

0.25V

0

3V

1.5V
0

t

PLZ

V

0.25V

CC

V

OL

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and
Slew-Rate-Limited True RS-485/RS-422 Transceivers

10 ______________________________________________________________________________________

V

ID

50Ω

C

L

= 15pF

(NOTE 5)

GENERATOR

(NOTE 4)

R

OUT

t

RPLH

1.5V

OUT

1.5V
0

IN

1.5V

3.0V

0

t

RPHL

V

CC

V

OM

V

OM

0

V

CC

2

V

OM

=

Figure 11. Receiver Propagation Delay

Figure 12. Receiver Enable and Disable Times

Note 4: The input pulse is supplied by a generator with the following characteristics: f = 250kHz, 50% duty cycle, tr≤ 6.0ns, ZO= 50Ω.
Note 5: C

L

includes probe and stray capacitance.

OUT

OUT

0.25V

S1

V

CC

S2

3V

0

V

V

3V

0

V

V

S1 CLOSED
S2 OPEN
S3 = -1.5V

CC

OL

S1 CLOSED
S2 OPEN
S3 = -1.5V

CC

OL

1.5V

t

PRLZ

t

PRZL

tPRSL

1.5V

1.5V

t

PRZH

tPRSH

t

PRHZ

S3

GENERATOR

(NOTE 4)

1.5V

1.5V

1k

V

ID

R

CL
(NOTE 5)

50Ω

3V

0

V

0

3V

0

V

0

S1 OPEN
S2 CLOSED
S3 = 1.5V

OH

S1 OPEN
S2 CLOSED
S3 = 1.5V

OH

IN

OUT

IN

OUT

1.5V

-1.5V

IN

IN

0.25V

1.5V

_____________________Function Tables

Devices with Receiver/Driver Enable

(MAX3483E/MAX3485E/MAX3486E/MAX3491E)

Table 1. Transmitting

* B and A outputs are Z and Y, respectively, for full-duplex part
(MAX3491E).
X = Don’t care; High-Z = High impedance

Table 2. Receiving

* DE is a “don’t care” (x) for the full-duplex part (MAX3491E).
X = Don’t care; High-Z = High impedance

Devices without Receiver/Driver Enable

(MAX3488E/MAX3490E)

Table 3. Transmitting Table 4. Receiving

___________Applications Information

The MAX3483E/MAX3485E/MAX3486E/MAX3488E/
MAX3490E/MAX3491E are low-power transceivers for
RS-485 and RS-422 communications. The MAX3483E
and MAX3488E can transmit and receive at data rates
up to 250kbps, the MAX3486E at up to 2.5Mbps, and the
MAX3485E/MAX3490E/MAX3491E at up to 12Mbps. The
MAX3488E/MAX3490E/MAX3491E are full-duplex trans­ceivers, while the MAX3483E/MAX3485E/MAX3486E are
half-duplex. Driver Enable (DE) and Receiver Enable
(RE) pins are included on the MAX3483E/MAX3485E/
MAX3486E/MAX3491E. When disabled, the driver and
receiver outputs are high impedance.

Reduced EMI and Reflections

(MAX3483E/MAX3486E/MAX3488E)

The MAX3483E/MAX3488E are slew-rate limited, mini­mizing EMI and reducing reflections caused by improp­erly terminated cables. Figure 13 shows the driver
output waveform of a MAX3485E/MAX3490E/MAX3491E
transmitting a 125kHz signal, as well as the Fourier
analysis of that waveform. High-frequency harmonics
with large amplitudes are evident. Figure 14 shows the
same information, but for the slew-rate-limited
MAX3483E/MAX3488E transmitting the same signal. The
high-frequency harmonics have much lower amplitudes,
and the potential for EMI is significantly reduced.

Low-Power Shutdown Mode

(MAX3483E/MAX3485E/MAX3486E/MAX3491E)

A low-power shutdown mode is initiated by bringing both
RE high and DE low. The devices will not shut down
unless both the driver and receiver are disabled (high
impedance). In shutdown, the devices typically draw
only 2nA of supply current.

For these devices, the t

PSH

and t

PSL

enable times
assume the part was in the low-power shutdown mode;
the t

PZH

and t

PZL

enable times assume the receiver or

driver was disabled, but the part was not shut down.

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and

Slew-Rate-Limited True RS-485/RS-422 Transceivers

______________________________________________________________________________________ 11

INPUTS OUTPUTS

RE

DE DI B* A*

MODE

X 1 1 0 1 Normal
X 1 0 1 0 Normal
0 0 X High-Z High-Z Normal
1 0 X High-Z High-Z Shutdown

INPUTS

RE

DE A, B RO

MODE

0 0* ≥ +0.2V 1 Normal
0 0* ≤ -0.2V 0 Normal
0 0* Inputs Open 1 Normal
1 0 X High-Z Shutdown

OUTPUTS

INPUTS OUTPUT

A, B RO

≥+0.2V 1

≤-0.2V 0

Inputs Open 1

INPUT OUTPUTS

DI Z Y

1 0 1
0 1 0

Figure 13. Driver Output Waveform and FFT Plot of MAX3485E/
MAX3490E/MAX3491E Transmitting a 125kHz Signal

Figure 14. Driver Output Waveform and FFT Plot of
MAX3483E/ MAX3488E Transmitting a 125kHz Signal

10dB/div

5MHz500kHz/div0

10dB/div

5MHz500kHz/div0

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and
Slew-Rate-Limited True RS-485/RS-422 Transceivers

12 ______________________________________________________________________________________

B

1V/div

A

1V/div

RO

2V/div

20ns/div

Figure 15. MAX3485E/MAX3490E/MAX3491E Driver Propagation
Delay

Figure 17. MAX3483E/MAX3488E Driver Propagation Delay

Figure 16. MAX3485E/MAX3490E/MAX3491E Receiver
Propagation Delay Driven by External RS-485 Device

Figure 18. MAX3483E/MAX3488E Receiver Propagation Delay

Figure 19. MAX3483E/MAX3488E System Differential Voltage at
125kHz Driving 4000 Feet of Cable

Figure 20. MAX3485E/MAX3490E/MAX3491E System Differential
Voltage at 125kHz Driving 4000 Feet of Cable

DI

2V/div

Z

1V/div

Y

1V/div

20ns/div

DI

2V/div

Z

1V/div

Y

1V/div

1µs/div

DI

5V/div

- V

V

Y

Z

2V/div

B

1V/div

A

1V/div

RO

2V/div

1µs/div

DI

5V/div

- V

V

Y

Z

2V/div

RO

5V/div

2µs/div

RO

5V/div

2µs/div

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and

Slew-Rate-Limited True RS-485/RS-422 Transceivers

______________________________________________________________________________________ 13

Driver-Output Protection

Excessive output current and power dissipation caused
by faults or by bus contention are prevented by two
mechanisms. 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

). In addition, a thermal shut­down circuit forces the driver outputs into a high-imped­ance state if the die temperature rises excessively.

Propagation Delay

Figures 15–18 show the typical propagation delays. Skew
time is simply the difference between the low-to-high and
high-to-low propagation delay. Small driver/receiver
skew times help maintain a symmetrical mark-space
ratio (50% duty cycle).

The receiver skew time, |t

PRLH

- t

PRHL|

, is under 10ns
(20ns for the MAX3483E/MAX3488E). The driver skew
times are 8ns for the MAX3485E/MAX3490E/MAX3491E,
12ns for the MAX3486E, and typically under 50ns for the
MAX3483E/MAX3488E.

Line Length vs. Data Rate

The RS-485/RS-422 standard covers line lengths up to
4000 feet. For line lengths greater than 4000 feet, see
Figure 21 for an example of a line repeater.

Figures 19 and 20 show the system differential voltage
for parts driving 4000 feet of 26AWG twisted-pair wire
at 125kHz into 120Ω loads.

For faster data rate transmission, please consult the fac­tory.

±15kV ESD Protection

As with all Maxim devices, ESD-protection structures are
incorporated on all pins to protect against electrostatic
discharges encountered during handling and assembly.
The driver outputs and receiver inputs of the MAX3483E
family of devices have extra protection against static
electricity. Maxim’s engineers have developed state-of­the-art structures to protect these pins against ESD of
±15kV without damage. The ESD structures withstand
high ESD in all states: normal operation, shutdown, and
powered down. After an ESD event, Maxim’s E versions
keep working without latchup or damage.

ESD protection can be tested in various ways; the
transmitter outputs and receiver inputs of this product
family are characterized for protection to the following
limits:

1) ±15kV using the Human Body Model

2) ±8kV using the Contact-Discharge method specified
in IEC 1000-4-2

3) ±15kV using IEC 1000-4-2’s Air-Gap method.

ESD Test Conditions

ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.

Human Body Model

Figure 22a shows the Human Body Model and Figure
22b shows the current waveform it generates when dis­charged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of inter­est, which is then discharged into the test device
through a 1.5kΩ resistor.

IEC 1000-4-2

The IEC 1000-4-2 standard covers ESD testing and
performance of finished equipment; it does not specifi­cally refer to integrated circuits. The MAX3483E family
of devices helps you design equipment that meets
Level 4 (the highest level) of IEC 1000-4-2, without the
need for additional ESD-protection components.

The major difference between tests done using the
Human Body Model and IEC 1000-4-2 is higher peak
current in IEC 1000-4-2, because series resistance is
lower in the IEC 1000-4-2 model. Hence, the ESD with­stand voltage measured to IEC 1000-4-2 is generally
lower than that measured using the Human Body
Model. Figure 23a shows the IEC 1000-4-2 model, and
Figure 23b shows the current waveform for the ±8kV
IEC 1000-4-2, Level 4 ESD contact-discharge test.

120Ω

120Ω

DATA IN

DATA OUT

R

D

RO
RE
DE

DI

A
B

Z
Y

MAX3488E
MAX3490E
MAX3491E

NOTE: RE AND DE ON MAX3491E ONLY.

Figure 21. Line Repeater for MAX3488E/MAX3490E/MAX3491E

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

The air-gap test involves approaching the device with a
charged probe. The contact-discharge method connects
the probe to the device before the probe is energized.

Machine Model

The Machine Model for ESD tests all pins using a
200pF storage capacitor and zero discharge resis­tance. Its objective is to emulate the stress caused
when I/O pins are contacted by handling equipment
during test and assembly. Of course, all pins require
this protection, not just RS-485 inputs and outputs.

Typical Applications

The MAX3483E/MAX3485E/MAX3486E/MAX3488E/
MAX3490E/MAX3491E transceivers are designed for
bidirectional data communications on multipoint bus
transmission lines. Figures 24 and 25 show typical net­work applications circuits. These parts can also be
used as line repeaters, with cable lengths longer than
4000 feet, as shown in Figure 21.

To minimize reflections, the line should be terminated at
both ends in its characteristic impedance, and stub
lengths off the main line should be kept as short as
possible. The slew-rate-limited MAX3483E/MAX3488E
and the partially slew-rate-limited MAX3486E are more
tolerant of imperfect termination.

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and
Slew-Rate-Limited True RS-485/RS-422 Transceivers

14 ______________________________________________________________________________________

CHARGE-CURRENT

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE
CAPACITOR

C

s

100pF

R

C

1M

R

D

1500Ω

HIGH-

VOLTAGE

DC

SOURCE

DEVICE

UNDER

TEST

Figure 22a. Human Body ESD Test Model

IP 100%

90%

36.8%

t

RL

TIME

t

DL

CURRENT WAVEFORM

PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)

I

r

10%

0

0

AMPERES

Figure 22b. Human Body Current Waveform

CHARGE-CURRENT

LIMIT RESISTOR

DISCHARGE

RESISTANCE

STORAGE
CAPACITOR

C

s

150pF

R

C

50M to 100M

R

D

330Ω

HIGH-

VOLTAGE

DC

SOURCE

DEVICE
UNDER

TEST

Figure 23a. IEC 1000-4-2 ESD Test Model

tr = 0.7ns to 1ns

30ns

60ns

t

100%

90%

10%

I

PEAK

I

Figure 23b. IEC 1000-4-2 ESD Generator Current Waveform

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and

Slew-Rate-Limited True RS-485/RS-422 Transceivers

______________________________________________________________________________________ 15

120Ω

120Ω

R

D

RO

RE

DE

DI

A

B

Y

120Ω

120Ω

DI

DI DIRO RO

RO

DE DE

DE

RE

RE

RE

Z

Z

Z

Z

Y

Y

Y

AA

A

BB

B

D

D

D

R

R

R

MAX3488E
MAX3490E
MAX3491E

NOTE: RE AND DE ON MAX3491E ONLY.

Figure 25. MAX3488E/MAX3490E/MAX3491E Full-Duplex RS-485 Network

DI RO DE

RE

A

B

RE

RERE

RO

RO

RO

DI

DI

DI

DE

DE

DE

D

D

D

R

R

R

B

B

B

A

A

A

120Ω

120Ω

D

R

MAX3483E
MAX3485E
MAX3486E

Figure 24. MAX3483E/MAX3485E/MAX3486E Typical RS-485 Network

MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E

3.3V -Powered, ±15kV ESD-Protected, 12Mbps and
Slew-Rate-Limited True RS-485/RS-422 Transceivers

TRANSISTOR COUNT: 761

Chip InformationOrdering Information (continued)

PART

MAX3486ECSA

MAX3486ECPA 0°C to +70°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

8 SO

8 Plastic DIP
MAX3486EESA
MAX3486EEPA -40°C to +85°C

-40°C to +85°C 8 SO
8 Plastic DIP

MAX3488ECSA
MAX3488ECPA 0°C to +70°C

0°C to +70°C 8 SO

8 Plastic DIP

MAX3488EESA
MAX3488EEPA -40°C to +85°C

-40°C to +85°C 8 SO
8 Plastic DIP

MAX3490ECSA
MAX3490ECPA 0°C to +70°C

0°C to +70°C 8 SO

8 Plastic DIP

MAX3490EESA
MAX3490EEPA -40°C to +85°C

-40°C to +85°C 8 SO
8 Plastic DIP

MAX3491ECSD
MAX3491ECPD 0°C to +70°C

0°C to +70°C 14 SO

14 Plastic DIP

MAX3491EESD
MAX3491EEPD -40°C to +85°C

-40°C to +85°C 14 SO
14 Plastic DIP

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

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