Maxim MAX491EESD, MAX491EEPD, MAX491ECSD, MAX491ECPD, MAX488EESA Datasheet

19-0410; Rev 3; 7/96

±15kV ESD-Protected, Slew-Rate-Limited,

Low-Power, RS-485/RS-422 Transceivers

_______________General Description

The MAX481E, MAX483E, MAX485E, MAX487E–MAX491E,
and MAX1487E are low-power transceivers for RS-485 and
RS-422 communications in harsh environments. Each driver
output and receiver input is protected against ±15kV electro­static discharge (ESD) shocks, without latchup. These parts
contain one driver and one receiver. The MAX483E,
MAX487E, MAX488E, and MAX489E feature reduced slew­rate 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
MAX481E, MAX485E, MAX490E, MAX491E, and MAX1487E
are not limited, allowing them to transmit up to 2.5Mbps.

These transceivers draw as little as 120µA supply current
when unloaded or when fully loaded with disabled drivers
(see

Selection Table

MAX483E, and MAX487E have a low-current shutdown
mode in which they consume only 0.5µA. 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 their 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 MAX487E and MAX1487E feature quarter-unit-load
receiver input impedance, allowing up to 128 transceivers
on the bus. The MAX488E–MAX491E are designed for full­duplex communications, while the MAX481E, MAX483E,
MAX485E, MAX487E, and MAX1487E are designed for half­duplex applications. For applications that are not ESD sen­sitive see the pin- and function-compatible MAX481,
MAX483, MAX485, MAX487–MAX491, and MAX1487.

). Additionally, the MAX481E,

________________________Applications

Low-Power RS-485 Transceivers
Low-Power RS-422 Transceivers

____________________________Features

♦ ESD Protection: ±15kV—Human Body Model
♦ Slew-Rate Limited for Error-Free Data

Transmission (MAX483E/487E/488E/489E)

♦ Low Quiescent Current:

120µA (MAX483E/487E/488E/489E)
230µA (MAX1487E)
300µA (MAX481E/485E/490E/491E)

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

(MAX481E/485E/490E/491E/1487E)

♦ Full-Duplex and Half-Duplex Versions Available
♦ Allows up to 128 Transceivers on the Bus

(MAX487E/MAX1487E)

♦ Current Limiting and Thermal Shutdown for

Driver Overload Protection

______________Ordering Information

PIN-PACKAGETEMP. RANGEPART

MAX481ECPA

Ordering Information continued on last page.

8 Plastic DIP0°C to +70°C
8 SO0°C to +70°CMAX481ECSA
8 Plastic DIP-40°C to +85°CMAX481EEPA
8 SO-40°C to +85°CMAX481EESA

Level Translators
Transceivers for EMI-Sensitive Applications
Industrial-Control Local Area Networks

______________________________________________________________Selection Table

PART

NUMBER

MAX481E
MAX483E
MAX485E
MAX487E
MAX488E
MAX489E
MAX490E
MAX491E

MAX1487E

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

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

________________________________________________________________

Maxim Integrated Products

1

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

±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, 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 (Y, Z; 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

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

PARAMETER SYMBOL MIN TYP MAX UNITS

Differential Driver Output (no load) V
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 V
Input Low Voltage V
Input Current I

Input Current
(A, B)

Receiver Differential Threshold
Voltage

Receiver Input Hysteresis ∆V
Receiver Output High Voltage V
Receiver Output Low Voltage V

Three-State (high impedance)
Output Current at Receiver

Receiver Input Resistance R

MIN

to T

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

MAX

OD1

V

∆V

∆V

R = 50Ω (RS-422)

OD2

R = 27Ω (RS-485), Figure 8

R = 27Ω or 50Ω, Figure 8

OD

V

R = 27Ω or 50Ω, Figure 8

OC

R = 27Ω or 50Ω, Figure 8

OD

DE, DI, –R—E

IH

DE, DI, –R—E

IL

DE, DI, –R—E

IN1

DE = 0V;
VCC= 0V or 5.25V,
all devices except

I

IN2

MAX487E/MAX1487E
MAX487E/MAX1487E,

DE = 0V, VCC= 0V or 5.25V

-7V ≤ VCM≤ 12V

V

TH

VCM= 0V

TH

IO= -4mA, VID= 200mV

OH

IO = 4mA, VID= -200mV

OL

I

0.4V ≤ VO≤ 2.4V

OZR

-7V ≤ VCM≤ 12V, all devices except
MAX487E/MAX1487E

IN

-7V ≤ V

CM

–
–
–

≤ 12V, MAX487E/MAX1487E 48 kΩ

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

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

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

Operating Temperature Ranges

MAX4_ _C_ _/MAX1487EC_ A.............................0°C to +70°C

MAX4_ _E_ _/MAX1487EE_ A...........................-40°C to +85°C

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

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

CONDITIONS

2

1.5 5

0.2 V

0.2 V

2.0 V

0.8 V
±2 µA

VIN= 12V

VIN= -7V
VIN= 12V

VIN= -7V

-0.2 0.2 V

3.5

12 kΩ

1.0

-0.8

0.25

-0.2

70 mV

0.4
±1 µA

5 V

V

3 V

mA

mA

V
V

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

2 _______________________________________________________________________________________

±15kV ESD-Protected, Slew-Rate-Limited,

Low-Power, 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

MAX488E/MAX489E,
DE, DI, –R—E–= 0V or V

MAX490E/MAX491E,
DE, DI, –R—E–= 0V or V

MAX481E/MAX485E,
–R—E–

I

CC

SHDN

OSD1

OSD2

I

OSR

= 0V or V

MAX1487E,
–R—E–

= 0V or V

MAX483E/MAX487E,
–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 = V
DE = 0V

CC

CC

MAX483E
MAX487E

CC

300 500

230 400

350 650

250 400

120 250

0.5 10I

7950V ≤ VO≤ V

SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E

(VCC= 5V ±5%, TA= T

PARAMETER SYMBOL MIN TYP MAX UNITS

Driver Input to Output
Driver Output Skew to Output

Driver Rise or Fall Time tR, t

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

Receiver Input to Output t

| t

- t

PLH

| Differential

PHL

Receiver Skew
Receiver Enable to Output Low t

Time to Shutdown t

MIN

to T

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

MAX

t

Figures 10 and 12, R

PLH

CL1= CL2= 100pF

t

PHL

t

SKEW

Figures 10 and 12, R
Figures 10 and 12,

R

F

ZH
ZL
LZ

t

HZ

= 54Ω,

DIFF

CL1= CL2= 100pF
Figures 11 and 13, CL= 100pF, S2 closed

Figures 11 and 13, CL= 100pF, S1 closed
Figures 11 and 13, CL= 15pF, S1 closed
Figures 11 and 13, CL= 15pF, S2 closed

Figures 10 and 14,

, t

R

PLH

t

SKD

ZL

t

ZH
LZ
HZ

MAX

SHDN

PHL

= 54Ω,

DIFF

CL1= CL2= 100pF
Figures 10 and 14, R

CL1= CL2= 100pF
Figures 9 and 15, CRL= 15pF, S1 closed
Figures 9 and 15, CRL= 15pF, S2 closed
Figures 9 and 15, CRL= 15pF, S1 closed
Figures 9 and 15, CRL= 15pF, S2 closed

MAX481E (Note 5)

CONDITIONS

= 54Ω,

DIFF

= 54Ω, CL1= CL2= 100pF

DIFF

MAX481E, MAX485E, MAX1487E

MAX481E, MAX485E, MAX1487E
MAX490EC/E, MAX491EC/E

= 54Ω,

DIFF

10 40 60
10 40 60

510

32040
52025MAX490EC/E, MAX491EC/E

45 70
45 70 ns
45 70
45 70

20 60 200
20 60 150

5 ns

20 50
20 50
20 50
20 50

2.5
50 200 600

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

µA

µAMAX481E/483E/487E, DE = 0V, –R—E–= V

mA35 250-7V ≤ VO≤12V (Note 4)I

mA35 250-7V ≤ VO≤12V (Note 4)I
mA

kV±15A, B, Y and Z pins, tested using Human Body ModelESD Protection

ns
ns

ns

ns

ns
ns

ns

ns
nsReceiver Enable to Output High
nsReceiver Disable Time from Low t
nsReceiver Disable Time from High t

MbpsMaximum Data Rate f

ns

_______________________________________________________________________________________ 3

±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers

SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E

(VCC= 5V ±5%, TA= T

Driver Enable from Shutdown to
Output High (MAX481E)

Driver Enable from Shutdown to
Output Low (MAX481E)

Receiver Enable from Shutdown
to Output High (MAX481E)

Receiver Enable from Shutdown
to Output Low (MAX481E)

MIN

to T

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

MAX

ZH(SHDN)

ZL(SHDN)

ZH(SHDN)

t

ZL(SHDN)

SWITCHING CHARACTERISTICS—MAX483E, MAX487E/MAX488E/MAX489E

(VCC= 5V ±5%, TA= T

Driver Input to Output

Driver Output Skew to Output ns20 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

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

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

I Differential

PHL

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)

(continued)

CONDITIONS

Figures 11 and 13, CL= 100pF, S2 closed

Figures 11 and 13, CL= 100pF, S1 closed

Figures 9 and 15, CL= 15pF, S2 closed,
A - B = 2V

Figures 9 and 15, CL= 15pF, S1 closed,
B - A = 2V

CONDITIONS

Figures 10 and 12, R
CL1= CL2= 100pF

Figures 10 and 12, R
CL1= CL2= 100pF

Figures 10 and 12, R

F

CL1= CL2= 100pF
Figures 11 and 13, CL= 100pF, S2 closed

Figures 11 and 13, CL= 100pF, S1 closed
Figures 11 and 13, CL= 15pF, S1 closed
Figures 11 and 13, CL= 15pF, S2 closed

Figures 10 and 14, R
CL1= CL2= 100pF

Figures 10 and 14, R
CL1= CL2= 100pF

Figures 9 and 15, CRL= 15pF, S1 closed
Figures 9 and 15, CRL= 15pF, S2 closed
Figures 9 and 15, CRL= 15pF, S1 closed
Figures 9 and 15, CRL= 15pF, S2 closed
t

, t

PLH

MAX483E/MAX487E, Figures 11 and 13,
CL= 100pF, S2 closed

MAX483E/MAX487E, Figures 11 and 13,
CL= 100pF, S1 closed

MAX483E/MAX487E, Figures 9 and 15,
CL= 15pF, S2 closed

MAX483E/MAX487E, Figures 9 and 15,
CL= 15pF, S1 closed

< 50% of data period

PHL

DIFF

DIFF

DIFF

DIFF

DIFF

= 54Ω,

= 54Ω,

= 54Ω,

= 54Ω,

= 54Ω,

225 1000

250 800 2000
250 800 2000

250 2000t

300 3000t
250 2000
250 2000

100

25 50t

UNITSMIN TYP MAXSYMBOLPARAMETER

ns45 100t

ns45 100t

ns225 1000t

ns

UNITSMIN TYP MAXSYMBOLPARAMETER

ns

ns250 2000tR, t
ns

ns250 2000t
ns300 3000t
ns

ns

ns
ns25 50t

ns25 50t
ns
ns25 50t

kbps250f

ns50 200 600MAX483E/MAX487E (Note 5) t
ns2000

ns2000

ns2500

ns2500

4 _______________________________________________________________________________________

±15kV ESD-Protected, Slew-Rate-Limited,

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

Typical Operating Characteristics.

= 5V and TA= +25°C.

CC

Note 5: The MAX481E/MAX483E/MAX487E 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

50
45
40
35
30
25
20
15

OUTPUT CURRENT (mA)

10

5
0

OUTPUT LOW VOLTAGE (V)

OUTPUT LOW VOLTAGE (V)

1.5 2.0 2.51.00.50

RECEIVER OUTPUT LOW VOLTAGE

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1
0

-60 -20 60

vs. TEMPERATURE

20 100-40 40080

TEMPERATURE (°C)

-25

MAX481E-01

-20

-15

-10

OUTPUT CURRENT (mA)

-5

0

I

= 8mA

RO

OUTPUT CURRENT vs.

RECEIVER OUTPUT HIGH VOLTAGE

1.5 3.0
OUTPUT HIGH VOLTAGE (V)

MAX481E-04

OUTPUT CURRENT (mA)

4.8

4.6

MAX481E-02

4.4

4.2

4.0

3.8

3.6

OUTPUT HIGH VOLTAGE (V)

3.4

3.2

3.0

5.04.54.02.0 2.5 3.5

DRIVER OUTPUT CURRENT vs.

DIFFERENTIAL OUTPUT VOLTAGE

90
80
70
60
50
40
30
20
10

0

1.5 2.0 2.5 3.0 3.5 4.0 4.51.00.50

DIFFERENTIAL OUTPUT VOLTAGE (V)

RECEIVER OUTPUT HIGH VOLTAGE

vs. TEMPERATURE

I

-60 -20 60

20 100-40 40080

TEMPERATURE (°C)

MAX481E-05

RO

= 8mA

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

MAX481E-03

_______________________________________________________________________________________

5

±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers

____________________________Typical Operating Characteristics (continued)

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

DRIVER DIFFERENTIAL OUTPUT

VOLTAGE vs. TEMPERATURE

2.3

2.2

2.1

2.0

1.9

1.8

1.7

1.6

DIFFERENTIAL OUTPUT VOLTAGE (V)

1.5

-60 -20 60

MAX481E/MAX485E/MAX490E/MAX491E

SUPPLY CURRENT vs. TEMPERATURE

600

500

400

300

200

SUPPLY CURRENT (µA)

100

0

-60 -20 60

20 100-40 40080

TEMPERATURE (°C)

MAX481E/MAX485E; DE = VCC, RE = X

MAX485E; DE = 0, RE = X,
MAX481E; DE = RE = 0
MAX490E/MAX491E; DE = RE = X

MAX481E; DE = 0, RE = V

20 100-40 40080

TEMPERATURE (°C)

R = 54Ω

CC

140

MAX481E-06

120

100

80
60

40

OUTPUT CURRENT (mA)

20

0

600

MAX481E-09

500

400

300

200

SUPPLY CURRENT (µA)

100

0

-60 -20 60

OUTPUT CURRENT vs.

DRIVER OUTPUT LOW VOLTAGE

MAX481E-07

024681012

OUTPUT LOW VOLTAGE (V)

MAX483E/MAX487E–MAX489E

SUPPLY CURRENT vs. TEMPERATURE

MAX481E-10

MAX483E; DE = VCC, RE = X

MAX487E; DE = VCC, RE = X


MAX483E/MAX487E; DE = RE = 0,
MAX488E/MAX489E; DE = RE = X

MAX483E/MAX487E; DE = 0, RE = V

20 100-40 40080

TEMPERATURE (°C)

CC

OUTPUT CURRENT vs.

DRIVER OUTPUT HIGH VOLTAGE

-100

-90

-80

-70

-60

-50

-40

-30

OUTPUT CURRENT (mA)

-20

-10
0

-8 -2
OUTPUT HIGH VOLTAGE (V)

SUPPLY CURRENT vs. TEMPERATURE

600

500

400

300

200

SUPPLY CURRENT (µA)

100

0

-60 -20 60

MAX1487E

MAX1487E; DE = VCC, RE = X


MAX1487E; DE = 0V, RE = X

20 100-40 40080

TEMPERATURE (°C)

MAX481E-08

642-6 -4 0

MAX481E-11

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

6 _______________________________________________________________________________________

±15kV ESD-Protected, Slew-Rate-Limited,

Low-Power, RS-485/RS-422 Transceivers

______________________________________________________________Pin Description

PIN

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

MAX481E/MAX483E
MAX485E/MAX487E

MAX1487E

1 2

2 —

3 —

4 3

5 4 Ground
— 5 Noninverting Driver Output
— 6 Inverting Driver Output

6 —
— 8 Noninverting Receiver Input

7 — Inverting Receiver Input and Inverting Driver Output
— 7 Inverting Receiver Input

8 1 Positive Supply: 4.75V ≤ VCC≤ 5.25V
— — No Connect—not internally connected

MAX488E
MAX490E

MAX489E
MAX491E

2

3

4

5

6, 7

9

10
—
12

—
11
14

1, 8, 13

NAME

RO

–R—E–

DE

DI

GND

Y
Z

A
A

B
B

V

CC

N.C.

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

Receiver Output Enable. RO is enabled when–R—E–is
low; RO is high impedance when–R—E–is high.

Driver Output Enable. The driver outputs, Y and Z, are
enabled by bringing DE high. They are high imped­ance when DE is low. If the driver outputs are enabled,
the parts function as line drivers. While they are high
impedance, they function as line receivers if–R—E–is low.

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.

Noninverting Receiver Input and Noninverting Driver
Output

FUNCTION

_______________________________________________________________________________________ 7

±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers

MAX481E

0.1µF

TOP VIEW

RO

2

RE

3

DE

4

D

DI

8

V

CC

7

B

6

A

5

GND

R

1

RO

RE
DE

R

1
2
3
4

D

DI

8

V

CC

B

7

Rt

6

A

5

GND

DIP/SO

NOTE: PIN LABELS Y AND Z ON TIMING, TEST, AND WAVEFORM DIAGRAMS REFER TO PINS A AND B WHEN DE IS HIGH.
TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.

Figure 1. MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E Pin Configuration and Typical Operating Circuit

MAX483E
MAX485E
MAX487E

MAX1487E

B

Rt

A

DE

DI

D

R

RO

RE

TOP VIEW

V

GND

0.1µF

V

1

CC



Y

3

A

1

CC

RO

R

2
3

DI

4

D

8

B

7
6

Z
Y

5

DI

RO

DR

2

5
6

Z

8

A

R

7

B

MAX488E
MAX490E



Rt

Rt

V

CC

RO

DI

D

DIP/SO

4

GND

NOTE: TYPICAL OPERATING CIRCUIT SHOWN WITH DIP/SO PACKAGE.

GND

Figure 2. MAX488E/MAX490E Pin Configuration and Typical Operating Circuit

V

CC

TOP VIEW

N.C.

GND
GND

1

R

2

RO

3

RE

4

DE

5

DI

6
7

14

V

CC

13

N.C.

DI

A

12

B

11
10

Z

D

9
8

Y
N.C.

RO

1, 8, 13

NC

DIP/SO

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

Figure 3. MAX489E/MAX491E Pin Configuration and Typical Operating Circuit

DE

5

D

2

RD

3 6, 7

RE

0.1µF

144

9
10

12
11

GND

MAX489E
MAX491E

Y

Z
A

Rt

B



VCCRE

Rt

R

GND DE

RO

DI

8 _______________________________________________________________________________________

±15kV ESD-Protected, Slew-Rate-Limited,

Low-Power, RS-485/RS-422 Transceivers

__________Function Tables

(MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E)

Table 1. Transmitting Table 2. Receiving

INPUTS OUTPUTS

RE

X

X

0

1

X = Don't care
High-Z = High impedance

Shutdown mode for MAX481E/MAX483E/MAX487E

*

DE DI Z Y

1

1

0

0

1

0

X

X

0

1

High-Z

High-Z

High-Z

High-Z

*

1

0

*

__________Applications Information

The MAX481E/MAX483E/MAX485E/MAX487E–MAX491E
and MAX1487E are low-power transceivers for RS-485
and RS-422 communications. These “E” versions of the
MAX481, MAX483, MAX485, MAX487–MAX491, and
MAX1487 provide extra protection against ESD. The
rugged MAX481E, MAX483E, MAX485E, MAX497E–
MAX491E, and MAX1487E are intended for harsh envi­ronments where high-speed communication is important.
These devices eliminate the need for transient suppres­sor diodes and the associated high capacitance loading.
The standard (non-“E”) MAX481, MAX483, MAX485,
MAX487–MAX491, and MAX1487 are recommended for
applications where cost is critical.

The MAX481E, MAX485E, MAX490E, MAX491E, and
MAX1487E can transmit and receive at data rates up to

2.5Mbps, while the MAX483E, MAX487E, MAX488E,
and MAX489E are specified for data rates up to
250kbps. The MAX488E–MAX491E are full-duplex
transceivers, while the MAX481E, MAX483E, MAX487E,
and MAX1487E are half-duplex. In addition, driver­enable (DE) and receiver-enable (RE) pins are included
on the MAX481E, MAX483E, MAX485E, MAX487E,
MAX489E, MAX491E, and MAX1487E. When disabled,
the driver and receiver outputs are high impedance.

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 have
extra protection against static electricity. Maxim’s engi-

±15kV ESD Protection

RE DE A-B RO

0

0

0

1

X = Don't care
High-Z = High impedance

Shutdown mode for MAX481E/MAX483E/MAX487E

*

neers developed state-of-the-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 MAX481E, MAX483E, MAX485E,
MAX487E–MAX491E, and MAX1487E keep working
without latchup.

ESD protection can be tested in various ways; the
transmitter outputs and receiver inputs of this product
family are characterized for protection to ±15kV using
the Human Body Model.

Other ESD test methodologies include IEC10004-2 con­tact discharge and IEC1000-4-2 air-gap discharge (for­merly IEC801-2).

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

Figure 4 shows the Human Body Model, and Figure 5
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.

The IEC1000-4-2 standard covers ESD testing and per­formance of finished equipment; it does not specifically
refer to integrated circuits (Figure 6).

INPUTS OUTPUT

0

0

0

0

> +0.2V

< -0.2V

Inputs open

X

1

0

1

High-Z

ESD Test Conditions

Human Body Model

IEC1000-4-2

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

*

_______________________________________________________________________________________ 9

±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers

1M RD 1500Ω

R

C

I

r

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

HIGH

VOLTAGE

DC

SOURCE

CHARGE CURRENT

LIMIT RESISTOR

Cs

100pF

DISCHARGE
RESISTANCE

STORAGE
CAPACITOR

DEVICE
UNDER

TEST

AMPERES

IP 100%

90%

36.8%
10%

0

0

t

RL

TIME

t

DL

CURRENT WAVEFORM

Figure 4. Human Body ESD Test Model

50M to 100M RD 330Ω

R

C

DISCHARGE

RESISTANCE

STORAGE

Cs

CAPACITOR

HIGH-

VOLTAGE

DC

SOURCE

CHARGE CURRENT

LIMIT RESISTOR

150pF

Figure 6. IEC1000-4-2 ESD Test Model

Y

R

V

OD

R

Z

Figure 5. Human Body Model Current Waveform

I

100%

90%

PEAK

I

DEVICE

UNDER

TEST

10%

tr = 0.7ns to 1ns

30ns

60ns

t

Figure 7. IEC1000-4-2 ESD Generator Current Waveform

TEST POINT

RECEIVER

OUTPUT

C

RL

15pF

V

OC

1k

1k

V

S1

S2

CC

Figure 8. Driver DC Test Load

Figure 9. Receiver Timing Test Load

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

10 ______________________________________________________________________________________

±15kV ESD-Protected, Slew-Rate-Limited,

Low-Power, RS-485/RS-422 Transceivers

3V

DE

Y

DI

Z

Figure 10. Driver/Receiver Timing Test Circuit Figure 11. Driver Timing Test Load

C

L1

A

R

V

DIFF

ID

B

C

L2

RO

RE

OUTPUT

UNDER TEST

500Ω

C

L

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

V

S1

S2

CC

3V

DI

1.5V

0V

t

PLH

1.5V

t

PHL

1/2 V

O

Z

V

O

Y

1/2 V

O

V

O

V

DIFF

0V

10%

-V

O

t

R

90%

V

= V (Y) - V (Z)

DIFF

t

SKEW =

90%

t

F

| t

- t

|

PLH

PHL

10%

3V

DE

1.5V 1.5V

0V

t

, t

ZL(SHDN)

Y, Z

Y, Z

V

OL

0V

2.3V

2.3V

ZL

OUTPUT NORMALLY LOW

OUTPUT NORMALLY HIGH

t

, t

ZH(SHDN)

ZH

t

LZ

V

+0.5V

OL

V

-0.5V

OH

t

HZ

Figure 12. Driver Propagation Delays Figure 13. Driver Enable and Disable Times (except MAX488E

and MAX490E)

3V

RE

V

OH

RO

V

OL

V

ID

A-B

0V

-V

ID

1.5V

OUTPUT

t

PHL

INPUT

1.5V

t

PLH

RO

0V

RO

1.5V 1.5V

0V

t

, t

V

CC

ZL(SHDN)

1.5V

OUTPUT NORMALLY LOW

OUTPUT NORMALLY HIGH

0V

1.5V

t

ZH(SHDN)

, t

t

LZ

ZL

VOL + 0.5V

V

- 0.5V

OH

t

ZH

HZ

Figure 14. Receiver Propagation Delays Figure 15. Receiver Enable and Disable Times (except MAX488E

and MAX490E)

______________________________________________________________________________________ 11

±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers



10dB/div

0Hz 5MHz

Figure 16. Driver Output Waveform and FFT Plot of
MAX485E/MAX490E/MAX491E/MAX1487E Transmitting a
150kHz Signal

The major difference between tests done using the
Human Body Model and IEC1000-4-2 is higher peak
current in IEC1000-4-2, because series resistance is
lower in the IEC1000-4-2 model. Hence, the ESD with­stand voltage measured to IEC1000-4-2 is generally
lower than that measured using the Human Body
Model. Figure 7 shows the current waveform for the 8kV
IEC1000-4-2 ESD contact-discharge test.

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.

500kHz/div

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 by
contact that occurs with handling and assembly during
manufacturing. Of course, all pins require this protec­tion during manufacturing—not just inputs and outputs.
Therefore, after PC board assembly, the Machine Model
is less relevant to I/O ports.

MAX487E/MAX1487E:

128 Transceivers on the Bus

The 48kΩ, 1/4-unit-load receiver input impedance of the
MAX487E and MAX1487E allows up to 128 transceivers
on a bus, compared to the 1-unit load (12kΩ input
impedance) of standard RS-485 drivers (32 transceivers
maximum). Any combination of MAX487E/MAX1487E
and other RS-485 transceivers with a total of 32 unit
loads or less can be put on the bus. The MAX481E,
MAX483E, MAX485E, and MAX488E–MAX491E have
standard 12kΩ receiver input impedance.

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

10dB/div

0Hz 5MHz

Figure 17. Driver Output Waveform and FFT Plot of
MAX483E/MAX487E–MAX489E Transmitting a 150kHz Signal

MAX483E/MAX487E/MAX488E/MAX489E:

Reduced EMI and Reflections

The MAX483E and MAX487E–MAX489E are slew-rate
limited, minimizing EMI and reducing reflections
caused by improperly terminated cables. Figure 16
shows the driver output waveform and its Fourier analy­sis of a 150kHz signal transmitted by a MAX481E,
MAX485E, MAX490E, MAX491E, or MAX1487E. High­frequency harmonics with large amplitudes are evident.
Figure 17 shows the same information displayed for a
MAX483E, MAX487E, MAX488E, or MAX489E transmit­ting under the same conditions. Figure 17’s high-fre­quency harmonics have much lower amplitudes, and
the potential for EMI is significantly reduced.

Low-Power Shutdown Mode

(MAX481E/MAX483E/MAX487E)

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.
In shutdown, the devices typically draw only 0.5µA of
supply current.

RE and DE may be driven simultaneously; the parts are
guaranteed not to enter shutdown if RE is high and DE
is low for less than 50ns. If the inputs are in this state
for at least 600ns, the parts are guaranteed to enter
shutdown.

For the MAX481E, MAX483E, and MAX487E, the t
and tZLenable times assume the part was not in the
low-power shutdown state (the MAX485E, MAX488E–
MAX491E, and MAX1487E can not be shut down). The
t

ZH(SHDN)

parts were shut down (see

and t

ZL(SHDN)



500kHz/div

enable times assume the

Electrical Characteristics

ZH

).

12 ______________________________________________________________________________________

±15kV ESD-Protected, Slew-Rate-Limited,

Low-Power, RS-485/RS-422 Transceivers

100pF

TTL IN

t

, tF < 6ns

R

Figure 18. Receiver Propagation Delay Test Circuit

Z

D

R = 54Ω

Y

100pF

B

A

RECEIVER

R

OUT

It takes the drivers and receivers longer to become
enabled from the low-power shutdown state (t
t

ZL(SHDN)

) than from the operating mode (tZH, tZL). (The

ZH(SHDN

parts are in operating mode if the RE, DE inputs equal a
logical 0,1 or 1,1 or 0, 0.)

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

Operating Characteristics

). In addition, a thermal shut-

Typical

down circuit forces the driver outputs into a high-imped­ance state if the die temperature rises excessively.

Propagation Delay

Many digital encoding schemes depend on the differ­ence between the driver and receiver propagation

delay times. Typical propagation delays are shown in
Figures 19–22 using Figure 18’s test circuit.

The difference in receiver delay times, t
typically under 13ns for the MAX481E, MAX485E,
MAX490E, MAX491E, and MAX1487E, and is typically
less than 100ns for the MAX483E and MAX487E–
MAX489E.

The driver skew times are typically 5ns (10ns max) for
the MAX481E, MAX485E, MAX490E, MAX491E, and
MAX1487E, and are typically 100ns (800ns max) for the
MAX483E and MAX487E–MAX489E.

Typical Applications

The MAX481E, MAX483E, MAX485E, MAX487E–
MAX491E, and MAX1487E transceivers are designed for
bidirectional data communications on multipoint bus
transmission lines. Figures 25 and 26 show typical net­work application circuits. These parts can also be used as
line repeaters, with cable lengths longer than 4000 feet.

,

)

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 MAX483E and MAX487E–
MAX489E are more tolerant of imperfect termination.
Bypass the VCCpin with 0.1µF.

Isolated RS-485

For isolated RS-485 applications, see the MAX253 and
MAX1480 data sheets.

Line Length vs. Data Rate

The RS-485/RS-422 standard covers line lengths up to
4000 feet. Figures 23 and 24 show the system differen­tial voltage for the parts driving 4000 feet of 26AWG
twisted-pair wire at 110kHz into 100Ω loads.

PLH

- t

PHL

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

, is

______________________________________________________________________________________ 13

±15kV ESD-Protected, Slew-Rate-Limited,



Low-Power, RS-485/RS-422 Transceivers



A

B

500mV/div

B

RO

5V/div

25ns/div

Figure 19. MAX481E/MAX485E/MAX490E/MAX1487E Receiver
t

PHL



A

500mV/div

B

RO

5V/div

200ns/div

Figure 21. MAX483E/MAX487E–MAX489E Receiver t

PHL



500mV/div

A

5V/div

RO

25ns/div

Figure 20. MAX481E/MAX485E/MAX490E/MAX491E/
MAX1487E Receiver t

PLH



B

500mV/div

A

5V/div

RO

200ns/div

Figure 22. MAX483E/MAX487E–MAX489E Receiver t



PLH

DI

V

- V

A

B

DO 0V

2µs/div

5V
0V

0

-1V

5V

Figure 23. MAX481E/MAX485E/MAX490E/MAX491E/
MAX1487E System Differential Voltage at 110kHz Driving

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

4000ft of Cable

DI

V

- V

B

A

DO

2µs/div

Figure 24. MAX483E/MAX1487E–MAX489E System Differential
Voltage at 110kHz Driving 4000ft of Cable

5V
0V

1V

0

-1V

5V
0V

14 ______________________________________________________________________________________

±15kV ESD-Protected, Slew-Rate-Limited,

Low-Power, RS-485/RS-422 Transceivers

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

120Ω

DI

B

120Ω

B

D

DE

RO
RE

R

A

MAX481E

B

A

R

D

B

A

A

R

D

MAX483E
MAX485E
MAX487E

DE

DI RO DE

DI

RO

RERE

MAX1487E

Figure 25. MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E Typical Half-Duplex RS-485 Network

A

120Ω

RO
RE

DE

DI

R

B

Z

D

120Ω

Y

Z

Y

AA

BB

Z

Y

R

D

DI DIRO RO

DE DE

RE

D

RE

120Ω

120Ω

R

DE

D

DI

R

Y

Z

B

R

A

RO
RE

DI

D

DE
RE

RO

MAX488E
MAX489E
MAX490E
MAX491E

NOTE: RE AND DE ON MAX489E/MAX491E ONLY.

Figure 26. MAX488E–MAX491E Full-Duplex RS-485 Network

______________________________________________________________________________________ 15

±15kV ESD-Protected, Slew-Rate-Limited,
Low-Power, RS-485/RS-422 Transceivers

___________________________________________Ordering Information (continued)

PIN-PACKAGETEMP. RANGEPART

MAX483ECPA

MAX485ECPA

MAX487ECPA

MAX488ECPA

8 Plastic DIP0°C to +70°C
8 SO0°C to +70°CMAX483ECSA
8 Plastic DIP-40°C to +85°CMAX483EEPA
8 SO-40°C to +85°CMAX483EESA
8 Plastic DIP0°C to +70°C
8 SO0°C to +70°CMAX485ECSA
8 Plastic DIP-40°C to +85°CMAX485EEPA
8 SO-40°C to +85°CMAX485EESA
8 Plastic DIP0°C to +70°C
8 SO0°C to +70°CMAX487ECSA
8 Plastic DIP-40°C to +85°CMAX487EEPA
8 SO-40°C to +85°CMAX487EESA
8 Plastic DIP0°C to +70°C
8 SO0°C to +70°CMAX488ECSA
8 Plastic DIP-40°C to +85°CMAX488EEPA
8 SO-40°C to +85°CMAX488EESA

___________________Chip Information

TRANSISTOR COUNT: 295

MAX489ECPD

MAX490ECPA

MAX491ECPD

MAX1487ECPA

PIN-PACKAGETEMP. RANGEPART

14 Plastic DIP0°C to +70°C
14 SO0°C to +70°CMAX489ECSD
14 Plastic DIP-40°C to +85°CMAX489EEPD
14 SO-40°C to +85°CMAX489EESD
8 Plastic DIP0°C to +70°C
8 SO0°C to +70°CMAX490ECSA
8 Plastic DIP-40°C to +85°CMAX490EEPA
8 SO-40°C to +85°CMAX490EESA
14 Plastic DIP0°C to +70°C
14 SO0°C to +70°CMAX491ECSD
14 Plastic DIP-40°C to +85°CMAX491EEPD
14 SO-40°C to +85°CMAX491EESD
8 Plastic DIP0°C to +70°C
8 SO0°C to +70°CMAX1487ECSA
8 Plastic DIP-40°C to +85°CMAX1487EEPA
8 SO-40°C to +85°CMAX1487EESA

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

16

__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 [phone]

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.