6

LT1080/LT1081

APPLICATIO S I FOR ATIO

The driver output stage of the LT1080 offers significantly

improved protection over older bipolar and CMOS de-

signs. In addition to current limiting, the driver output can

be externally forced to

±30V with no damage or excessive

current flow, and will not disrupt the supplies. Some

drivers have diodes connected between the outputs and

the supplies, so externally applied voltages can cause

excessive supply voltage to develop.

Placing the LT1080 in the SHUTDOWN mode (Pin 18 low)

puts both the driver and receiver outputs in a high imped-

ance state. This allows data line sharing and transceiver

applications.

The SHUTDOWN mode also drops input supply current

1080/81 F03

LT1080 #1

DRIVER

LOGIC

TRANSMIT/RECEIVE

LINE

RS232

TRANSMIT/RECEIVE

LINE

LOGIC

INVERTER

ON/OFF

(TRANSMIT/

RECEIVE)

INPUT

LT1080 #2

RECEIVER

30V

–30V

OUTPUT CAN

BE FORCED

EXTERNALLY

1080/81 F01

LT1080/LT1081 Driver

Transceiver

Sharing a Receiver Line

Sharing a Transmitter Line

Older RS232 Drivers and CMOS Drivers

WITH SOME DRIVERS,

EXTERNALLY APPLIED

VOLTAGE CAN FORCE

THE SUPPLIES

1080/81 F02

LT1080 #1

RECEIVER

1080/81 F04

RS232

INPUT A

RS232

INPUT B

LOGIC

OUTPUT

LOGIC

INVERTER

ON/OFF

(CHANNEL

SELECT)

INPUT

LT1080 #2

RECEIVER

LT1080 #1

DRIVER

LOGIC

INPUT A

LOGIC

INPUT B

RS232

TRANSMISSION

LINE

LT1080 #2

DRIVER

1080/81 F05

LOGIC

INVERTER

ON/OFF

(CHANNEL

SELECT)

INPUT