Low-Power, Slew-Rate-Limited

RS-485/RS-422 Transceivers

Maxim Integrated

7

MAX481/MAX483/MAX485/

MAX487–MAX491/MAX1487

______________________________________________________________Pin Description

MAX481

MAX483

MAX485

MAX487

MAX1487

TOP VIEW

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.

1

2

3

4

8

5

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

B

A

GND

DI

DE

RE

RO

DIP/SO

R

D

1

2

3

4

8

7

6

5

A

GND

DE

RE

B

RO

μMAX

B

A

DI

MAX481

MAX483

MAX485

MAX487

MAX1487

Figure 1. MAX481/MAX483/MAX485/MAX487/MAX1487 Pin Configuration and Typical Operating Circuit

µMAX

—

—

5

6

7

8

—

2

—

1

3

—

µMAX

4

5

6

7

—

—

8

—

1

—

2

—

DIP/SO

DIP/SO

2

3

Receiver Output Enable. RO is enabled when RE is low; RO is

high impedance when RE is high.

3

4

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

RE is low.

DIP/SO

—

4

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.

5

6, 7

Ground

—

9

Noninverting Driver Output

—

10

Inverting Driver Output

—

3

4

6

—

Noninverting Receiver Input and Noninverting Driver Output

—

12

Noninverting Receiver Input

5

6

—

8

RE

DE

DI

GND

Y

Z

A

A

7

—

—

B

Inverting Receiver Input and Inverting Driver Output

—

7

11

B

Inverting Receiver Input

8

1

14

Positive Supply: 4.75V

—

—

1, 8, 13

N.C.

No Connect—not internally connected

FUNCTION

NAME

4

3

1

2

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

If A < B by 200mV, RO will be low.

2

RO

PIN

FUNCTION

NAME

MAX481/MAX483/

MAX485/MAX487/

MAX1487

MAX488/

MAX490

MAX489/

MAX491