Half-Duplex RS-485/RS-422 Transceivers in µDFN

10

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Pin Description

PIN

NAME

FUNCTION

1

RO

Receiver Output

2

RE

Receiver Output Enable. Drive RE low to enable RO. RO is high impedance when RE is high. Drive

RE high and DE low to enter low-power shutdown mode. RE is a hot-swap input (see the Hot-Swap

Capability section for more details).

3DE

Driver Output Enable. Drive DE high to enable the driver outputs. These outputs are high-impedance

when DE is low. Drive RE high and DE low to enter low-power shutdown mode. DE is a hot-swap input

(see the Hot-Swap Capability section for more details).

4DI

Driver Input. Drive DI low to force noninverting output low and inverting output high. Drive DI high to

force noninverting output high and inverting output low (see the Function Tables).

5

GND

Ground

6

A

Noninverting Receiver Input and Noninverting Driver Output

7

B

Inverting Receiver Input and Inverting Driver Output

TRANSMITTING

INPUT

OUTPUT

RE

DE

DI

B

A

X1

1

0

1

X1

0

1

0

0

0

X

HIGH IMPEDANCE

HIGH IMPEDANCE

1

0

X

SHUTDOWN

RECEIVING

INPUT

OUTPUT

RE

DE

A-B

RO

0X

> -50mV

1

0X

< -200mV

0

0

X

OPEN/SHORT

1

1

1

X

HIGH IMPEDANCE

1

0

X

SHUTDOWN

Function Tables

X = Don’t care, shutdown mode, driver, and receiver outputs

are in high impedance.