Maxim MAX491MJD, MAX491ESD, MAX491EPD, MAX488MJA, MAX488ESA Datasheet

19-0122; Rev 5; 2/96

Low-Power, Slew-Rate-Limited

RS-485/RS-422 Transceivers

_______________General Description

The MAX481, MAX483, MAX485, MAX487–MAX491, and
MAX1487 are low-power transceivers for RS-485 and RS­422 communication. Each part contains one driver and one
receiver. The MAX483, MAX487, MAX488, and MAX489
feature reduced slew-rate drivers that minimize EMI and
reduce reflections caused by improperly terminated cables,
thus allowing error-free data transmission up to 250kbps.
The driver slew rates of the MAX481, MAX485, MAX490,
MAX491, and MAX1487 are not limited, allowing them to
transmit up to 2.5Mbps.

These transceivers draw between 120µA and 500µA of
supply current when unloaded or fully loaded with disabled
drivers. Additionally, the MAX481, MAX483, and MAX487
have a low-current shutdown mode in which they consume
only 0.1µA. All parts operate from a single 5V supply.

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 the input is open circuit.

The MAX487 and MAX1487 feature quarter-unit-load
receiver input impedance, allowing up to 128 MAX487/
MAX1487 transceivers on the bus. Full-duplex communi­cations are obtained using the MAX488–MAX491, while
the MAX481, MAX483, MAX485, MAX487, and MAX1487
are designed for half-duplex applications.

____________________________Features

♦ In µMAX Package: Smallest 8-Pin SO
♦ Slew-Rate Limited for Error-Free Data

Transmission (MAX483/487/488/489)

♦ 0.1µA Low-Current Shutdown Mode

(MAX481/483/487)

♦ Low Quiescent Current:

120µA (MAX483/487/488/489)
230µA (MAX1487)
300µA (MAX481/485/490/491)

♦ -7V to +12V Common-Mode Input Voltage Range
♦ Three-State Outputs
♦ 30ns Propagation Delays, 5ns Skew

(MAX481/485/490/491/1487)

♦ Full-Duplex and Half-Duplex Versions Available
♦ Operate from a Single 5V Supply
♦ Allows up to 128 Transceivers on the Bus

(MAX487/MAX1487)

♦ Current-Limiting and Thermal Shutdown for

Driver Overload Protection

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487

________________________Applications

Low-Power RS-485 Transceivers
Low-Power RS-422 Transceivers
Level Translators
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks

______________Ordering Information

PART TEMP. RANGE PIN-PACKAGE

MAX481CPA

MAX481CSA 0°C to +70°C 8 SO
MAX481CUA 0°C to +70°C 8 µMAX
MAX481C/D 0°C to +70°C Dice*

Ordering Information continued at end of data sheet.

0°C to +70°C 8 Plastic DIP

* Contact factory for dice specifications.

______________________________________________________________Selection Table

PART

NUMBER

MAX481
MAX483
MAX485
MAX487
MAX488
MAX489
MAX490
MAX491

MAX1487

HALF/FULL

DUPLEX

Half
Half
Half
Half

Full
Full
Full
Full

Half

DATA RATE

(Mbps)

2.5

0.25

2.5

0.25

0.25

0.25

2.5

2.5

2.5

________________________________________________________________

SLEW-RATE

LIMITED

No

Yes

No
Yes
Yes
Yes

No

No

No

LOW-POWER

SHUTDOWN

Yes
Yes

No

Yes

No
No
No
No
No

RECEIVER/

DRIVER

ENABLE

Yes
Yes
Yes
Yes

No

Yes

No
Yes
Yes

QUIESCENT

CURRENT

(µA)

300
120
300
120
120
120
300
300
230

NUMBER OF

TRANSMITTERS

ON BUS

32
32
32

128

32
32
32
32

128

PIN

COUNT

8
8
8
8
8

14

8

14

8

Maxim Integrated Products

1

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

Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (VCC).............................................................12V

Control Input Voltage (–R—E–, DE)...................-0.5V to (V

Driver Input Voltage (DI).............................-0.5V to (V

Driver Output Voltage (A, B)...................................-8V to +12.5V

Receiver Input Voltage (A, B).................................-8V to +12.5V

Receiver Output Voltage (RO).....................-0.5V to (V

Continuous Power Dissipation (T

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

14-Pin Plastic DIP (derate 10.00mW/°C above +70°C)..800mW

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

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.

= +70°C)

A

CC
CC

CC

+ 0.5V)
+ 0.5V)

+0.5V)

DC ELECTRICAL CHARACTERISTICS

(VCC= 5V ±5%, TA= T

Differential Driver Output (no load)
Differential Driver Output

(with load)

Change in Magnitude of Driver
Differential Output Voltage for
Complementary Output States

Driver Common-Mode Output
Voltage

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

Input High Voltage
Input Low Voltage
Input Current

Input Current
(A, B)

Receiver Differential Threshold
Voltage

Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage

Three-State (high impedance)
Output Current at Receiver

Receiver Input Resistance

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487

MIN

to T

, unless otherwise noted.) (Notes 1, 2)

MAX

OD1

V

I

V

OZR

R

OD2

OC

IN1

IN2

OH

R = 50Ω (RS-422)
R = 27Ω (RS-485), Figure 4

R = 27Ω or 50Ω, Figure 4

OD

R = 27Ω or 50Ω, Figure 4

R = 27Ω or 50Ω, Figure 4

OD

DE, DI, –R—E

IH

DE, DI, –R—E

IL

DE, DI, –R—E
DE = 0V;

VCC= 0V or 5.25V,
all devices except
MAX487/MAX1487

MAX487/MAX1487,
DE = 0V, VCC= 0V or 5.25V

-7V ≤ VCM≤ 12V

TH

VCM= 0V

TH

IO= -4mA, VID= 200mV
IO = 4mA, VID= -200mV

OL

0.4V ≤ VO≤ 2.4V

-7V ≤ VCM≤ 12V, all devices except
MAX487/MAX1487

IN

CM

–
–
–

≤ 12V, MAX487/MAX1487

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

8-Pin µMAX (derate 4.1mW/°C above +70°C)..............830mW

8-Pin CERDIP (derate 8.00mW/°C above +70°C).........640mW

14-Pin CERDIP (derate 9.09mW/°C above +70°C).......727mW

Operating Temperature Ranges

MAX4_ _C_ _/MAX1487C_ A ...............................0°C to +70°C

MAX4_ _E_ _/MAX1487E_ A.............................-40°C to +85°C

MAX4_ _MJ_/MAX1487MJA ...........................-55°C to +125°C

Storage Temperature Range.............................-65°C to +160°C

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

CONDITIONS

2

1.5 5

VIN= 12V

VIN= -7V
VIN= 12V

VIN= -7V

3.5V

1.0

-0.8

0.25

-0.2

0.4V

UNITSMIN TYP MAXSYMBOLPARAMETER

V5V
V

V0.2∆V

V3V

V0.2∆V

V2.0V
V0.8V

µA±2I

mA

mA

V-0.2 0.2

mV70∆V

V
V

µA±1I

kΩ12

kΩ48-7V ≤ V

2 _______________________________________________________________________________________

Low-Power, Slew-Rate-Limited

RS-485/RS-422 Transceivers

DC ELECTRICAL CHARACTERISTICS (continued)

(VCC= 5V ±5%, TA= T

No-Load Supply Current
(Note 3)

Supply Current in Shutdown
Driver Short-Circuit Current,

VO= High
Driver Short-Circuit Current,

VO= Low
Receiver Short-Circuit Current

MIN

to T

, unless otherwise noted.) (Notes 1, 2)

MAX

MAX488/MAX489,
DE, DI, –R—E–= 0V or V

MAX490/MAX491,
DE, DI, –R—E–= 0V or V

MAX481/MAX485,
–R—E–

I

CC

SHDN

OSD1

OSD2

I

OSR

= 0V or V

MAX1487,
–R—E–

= 0V or V

MAX483/MAX487,
–R—E–

= 0V or V

CC

CC

CC

CC

CONDITIONS UNITSMIN TYP MAXSYMBOLPARAMETER

CC

CC

DE = V

CC

120 250

300 500
500 900

300 500DE = 0V
DE = V
DE = 0V

DE = 5V
DE = 0V

CC

MAX483
MAX487

CC

300 500

230 400

350 650

250 400

120 250

0.1 10I

7950V ≤ VO≤ V

SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487

(VCC= 5V ±5%, TA= T

Driver Input to Output
Driver Output Skew to Output

Driver Rise or Fall Time

Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High

Receiver Input to Output

| t

- t

PLH

| Differential

PHL

Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time from High
Maximum Data Rate
Time to Shutdown

MIN

to T

, unless otherwise noted.) (Notes 1, 2)

MAX

PLH
PHL

SKEW

Figures 6 and 8, R
CL1= CL2= 100pF

Figures 6 and 8, R
Figures 6 and 8,

R

t

, t

R

F

DIFF

= 54Ω,

CL1= CL2= 100pF
Figures 7 and 9, CL= 100pF, S2 closed

ZH

Figures 7 and 9, CL= 100pF, S1 closed

ZL

Figures 7 and 9, CL= 15pF, S1 closed

LZ

Figures 7 and 9, CL= 15pF, S2 closed

HZ

Figures 6 and 10,
R

t

PLH

, t

PHL

DIFF

= 54Ω,

CL1= CL2= 100pF

t

SKD

MAX

SHDN

Figures 6 and 10, R
CL1= CL2= 100pF

Figures 5 and 11, CRL= 15pF, S1 closed

ZL

Figures 5 and 11, CRL= 15pF, S2 closed

ZH

Figures 5 and 11, CRL= 15pF, S1 closed

LZ

Figures 5 and 11, CRL= 15pF, S2 closed

HZ

MAX481 (Note 5)

CONDITIONS

DIFF

= 54Ω,

10 30 60t
10 30 60t

= 54Ω, CL1= CL2= 100pF

DIFF

MAX481, MAX485, MAX1487
MAX490C/E, MAX491C/E
MAX490M, MAX491M

31540
51525
31540

510t

40 70t
40 70t

40 70t

MAX481, MAX485, MAX1487

20 90 200
MAX490C/E, MAX491C/E 20 90 150
MAX490M, MAX491M

= 54Ω,

DIFF

20 90 200

13

20 50t

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487

µA

µAMAX481/483/487, DE = 0V, –R—E–= V

mA35 250-7V ≤ VO≤12V (Note 4)I

mA35 250-7V ≤ VO≤12V (Note 4)I
mA

UNITSMIN TYP MAXSYMBOLPARAMETER

ns
ns

ns

ns
ns
ns40 70t
ns

ns

ns
ns20 50t

ns20 50t
ns
ns20 50t

Mbps2.5f

ns50 200 600t

_______________________________________________________________________________________ 3

Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers

SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487 (continued)

(VCC= 5V ±5%, TA= T

Driver Enable from Shutdown to
Output High (MAX481)

Driver Enable from Shutdown to
Output Low (MAX481)

Receiver Enable from Shutdown
to Output High (MAX481)

Receiver Enable from Shutdown
to Output Low (MAX481)

MIN

to T

, unless otherwise noted.) (Notes 1, 2)

MAX

ZH(SHDN)

ZL(SHDN)

ZH(SHDN)

t

ZL(SHDN)

Figures 7 and 9, CL= 100pF, S2 closed

Figures 7 and 9, CL= 100pF, S1 closed

Figures 5 and 11, CL= 15pF, S2 closed,
A - B = 2V

Figures 5 and 11, CL= 15pF, S1 closed,
B - A = 2V

CONDITIONS

300 1000

UNITSMIN TYP MAXSYMBOLPARAMETER

ns40 100t

ns40 100t

ns300 1000t

ns

SWITCHING CHARACTERISTICS—MAX483, MAX487/MAX488/MAX489

(VCC= 5V ±5%, TA= T

Driver Input to Output

Driver Output Skew to Output ns100 800

Driver Rise or Fall Time
Driver Enable to Output High

Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High

Receiver Input to Output

I t

- t

PLH

I Differential

PHL

Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time from High
Maximum Data Rate
Time to Shutdown
Driver Enable from Shutdown to

Output High
Driver Enable from Shutdown to

Output Low
Receiver Enable from Shutdown

to Output High
Receiver Enable from Shutdown

to Output Low

MIN

to T

, unless otherwise noted.) (Notes 1, 2)

MAX

t

PLH

t

PHL

t

SKEW

ZH

ZL
LZ

HZ

t

PLH

t

PHL

t

SKD

ZL

ZH

LZ

HZ

MAX

SHDN

t

ZH(SHDN)

t

ZL(SHDN)

t

ZH(SHDN)

t

ZL(SHDN)

Figures 6 and 8, R
CL1= CL2= 100pF

Figures 6 and 8, R
CL1= CL2= 100pF

Figures 6 and 8, R

F

CL1= CL2= 100pF
Figures 7 and 9, CL= 100pF, S2 closed

Figures 7 and 9, CL= 100pF, S1 closed
Figures 7 and 9, CL= 15pF, S1 closed
Figures 7 and 9, CL= 15pF, S2 closed

Figures 6 and 10, R
CL1= CL2= 100pF

Figures 6 and 10, R
CL1= CL2= 100pF

Figures 5 and 11, CRL= 15pF, S1 closed
Figures 5 and 11, CRL= 15pF, S2 closed
Figures 5 and 11, CRL= 15pF, S1 closed
Figures 5 and 11, CRL= 15pF, S2 closed
t

, t

PLH

PHL

MAX483/MAX487, Figures 7 and 9,
CL= 100pF, S2 closed

MAX483/MAX487, Figures 7 and 9,
CL= 100pF, S1 closed

MAX483/MAX487, Figures 5 and 11,
CL= 15pF, S2 closed

MAX483/MAX487, Figures 5 and 11,
CL= 15pF, S1 closed

CONDITIONS

= 54Ω,

DIFF

= 54Ω,

DIFF

= 54Ω,

DIFF

= 54Ω,

DIFF

= 54Ω,

DIFF

< 50% of data period

250 800 2000
250 800 2000

250 2000t

300 3000t
250 2000
250 2000

100

20 50t

UNITSMIN TYP MAXSYMBOLPARAMETER

ns

ns250 2000tR, t
ns

ns250 2000t
ns300 3000t
ns

ns

ns
ns20 50t

ns20 50t
ns
ns20 50t

kbps250f

ns50 200 600MAX483/MAX487 (Note 5) t
ns2000

ns2000

ns2500

ns2500

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487

4 _______________________________________________________________________________________

Low-Power, Slew-Rate-Limited

RS-485/RS-422 Transceivers

NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICS

Note 1: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device

ground unless otherwise specified.

Note 2: All typical specifications are given for V

= 5V and TA= +25°C.

CC

Note 3: Supply current specification is valid for loaded transmitters when DE = 0V.
Note 4: Applies to peak current. See

Typical Operating Characteristics.

Note 5: The MAX481/MAX483/MAX487 are put into shutdown by bringing–R—E–high and DE low. If the inputs are in this state for less

than 50ns, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 600ns, the parts are
guaranteed to have entered shutdown. See

Low-Power Shutdown Mode

section.

__________________________________________Typical Operating Characteristics

(VCC= 5V, TA = +25°C, unless otherwise noted.)

OUTPUT CURRENT vs.

RECEIVER OUTPUT LOW VOLTAGE

45
40
35

30
25
20
15

OUTPUT CURRENT (mA)

10

5
0

0.5 1.0 2.0

0 2.5

OUTPUT LOW VOLTAGE (V)

1.5

-20

-18

MAX481-01

-16

-14

-12

-10

-8

-6

OUTPUT CURRENT (mA)

-4

-2
0

1.5 2.0 3.0 5.0

OUTPUT CURRENT vs.

RECEIVER OUTPUT HIGH VOLTAGE

2.5 4.0

OUTPUT HIGH VOLTAGE (V)

3.5 4.5

RECEIVER OUTPUT HIGH VOLTAGE vs.

4.8

4.6

MAX481-02

4.4

4.2

4.0

3.8

3.6

3.4

OUTPUT HIGH VOLTAGE (V)

3.2

3.0

-50 -25 25 75

TEMPERATURE

IRO = 8mA

050
TEMPERATURE (°C)

100

125

MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487

MAX481-03

RECEIVER OUTPUT LOW VOLTAGE vs.

TEMPERATURE

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

OUTPUT LOW VOLTAGE (V)

0.1
0

-50 -25 25 75

050
TEMPERATURE (°C)

_______________________________________________________________________________________

IRO = 8mA

100

125

90

MAX481-04

80
70
60
50
40
30

OUTPUT CURRENT (mA)

20
10

0

DRIVER OUTPUT CURRENT vs.

DIFFERENTIAL OUTPUT VOLTAGE

0 1.0 3.0 4.5

0.5 1.5 2.5 3.5
DIFFERENTIAL OUTPUT VOLTAGE (V)

2.0 4.0

DRIVER DIFFERENTIAL OUTPUT VOLTAGE

vs. TEMPERATURE

2.4

2.3

MAX481-05

2.2

2.1

2.0

1.9

1.8

1.7

DIFFERENTIAL OUTPUT VOLTAGE (V)

1.6

1.5

-50 -25 25 125

075
TEMPERATURE (°C)

R = 54Ω

10050

MAX481-06

5