±80V Fault-Protected, Fail-Safe,

1/4-Unit Load, +3.3V RS-485 Transceiver

8

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Pin Description

PIN

NAME

FUNCTION

1

RO

Receiver Output

2

RE

Receiver Output Enable. RO is enabled when RE is low; RO is high impedance when RE is high. The

device enters a low-power shutdown mode if RE is high and DE is low.

3DE

Driver Output Enable. Driving DE high enables the driver outputs. Pulling DE low puts the driver

outputs in a high-impedance state. If RE is high and DE is low, the device enters a low-power

shutdown mode. If the driver outputs are enabled, the device functions as a line driver, and when

they are high impedance it functions as a line receiver if RE is low.

4DI

Driver Input. A logic low on DI forces output A low and output B high, while a logic high on DI forces

output A high and output B low.

5

GND

Ground

6

A

Noninverting Receiver Input/Driver Output

7

B

Inverting Receiver Input/Driver Output

Function Tables

Table 1. Transmitting

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

Table 2. Receiving

INPUTS

OUTPUTS

RE

DE

(A - B)

RO

MODE

00

≥ -50mV

1

Normal

00

≤ -200mV

0

Normal

00

Inputs

open

1

Normal

1

0

X

High-Z

Shutdown

X = Don’t care.

X = Don’t care.