10

LTC1345

RS422/RS485 Applications

The receivers on the LTC1345 are ideal for RS422 and

RS485 applications. Using the test circuit in Figure 9, the

LTC1345 receivers are able to successfully reconstruct

the data stream with the common-mode voltage meeting

RS422 and RS485 requirements (12V to – 7V).

Figures 10 and 11 show that the LTC1345 receivers are

very capable of reconstructing data at rates up to 10Mbaud.

Figure 10. – 7V Common Mode

LTC1345 • F10

RECEIVER

OUTPUT

5V/DIV

B

A

–10V

–5V

0V

0

5

Figure 11. 12V Common Mode

RECEIVER

OUTPUT

5V/DIV

15V

5

0

LTC1345 • F11

10V

5V

0V

RECEIVER

INPUT

5V/DIV

B

A

RECEIVER

INPUT

5V/DIV

LTC485

12V TO – 7V

COMMON-MODE VOLTAGE

5V

100

Ω

100

Ω

ABX

B

AX

GND

LTC1345 • F09

LTC1345

5V

GND

TTL

IN

TTL

OUT

– +

Figure 9 RS422/RS485 Receiver Interface