LT1039A_01 Datasheet, PDF (6/12 Pages) Linear Technology – Triple RS232 Driver/Receiver with Shutdown

LT1039A/LT1039A-16
APPLICATIONS INFORMATION
The driver output stage of the LT1039A offers signifi-
cantly improved protection over older bipolar and CMOS
designs. In addition to current limiting, the driver output
can be externally forced to ±30V with no damage or
excessive current flow.
Sharing a Receiver Line
RS232
INPUT A
LT1039A #1
RECEIVER
LT1039A Driver
LT1039A
OUTPUT CAN
BE FORCED
EXTERNALLY
30V
– 30V
1039A AI01
The driver outputs utilize high impedance overvoltage
protection, eliminating the flow of fault currents into
supplies, as will happen with conventional diode clamp
configurations.
RS232
INPUT B
ON/OFF
(CHANNEL SELECT)
INPUT
LT1039A #2
RECEIVER
LOGIC
INVERTER
1039A AI04
Transceiver
LOGIC
OUTPUT
Older RS232 Drivers and Other CMOS Drivers
V⁺
WITH SOME DRIVERS,
EXTERNALLY APPLIED
VOLTAGE CAN FORCE
THE SUPPLIES
V^–
1039A AI02
LOGIC
TRANSMIT/RECEIVE
LINE
LT1039A #1
DRIVER
LT1039A #2
RECEIVER
RS232
TRANSMIT/RECEIVE
LINE
Placing the LT1039A in the shutdown mode (Pin 17 low)
puts both the driver and receiver outputs in a high imped-
ance state. This allows data line sharing and transceiver
applications.
Sharing a Transmitter Line
ON/OFF
(TRANSMIT/RECEIVE)
INPUT
LOGIC
INVERTER
1039A AI05
The shutdown mode also drops all supply currents (V_CC,
V ⁺, V ^–) to zero for power conscious systems.
LOGIC
INPUT A
LT1039A #1
DRIVER
LOGIC
INPUT B
ON/OFF
(CHANNEL SELECT)
INPUT
6
LT1039A #2
DRIVER
LOGIC
INVERTER
1039A AI03
RS232
TRANSMISSION
LINE
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