LT1039A_15 Datasheet, PDF (6/14 Pages) Linear Technology – Triple RS232 Driver/Receiver with Shutdown

LT1039A/LT1039A-16
Applications Information
The driver output stage of the LT1039A offers significantly
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.
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.
Older RS232 Drivers and Other CMOS Drivers
V⁺
WITH SOME DRIVERS,
EXTERNALLY APPLIED
VOLTAGE CAN FORCE
THE SUPPLIES
V^–
1039A AI02
Sharing a Receiver Line
RS232
INPUT A
LT1039A #1
RECEIVER
RS232
INPUT B
LT1039A #2
RECEIVER
LOGIC
OUTPUT
ON/OFF
(CHANNEL SELECT)
INPUT
LOGIC
INVERTER
1039A AI04
Transceiver
LOGIC
TRANSMIT/RECEIVE
LINE
LT1039A #1
DRIVER
RS232
TRANSMIT/RECEIVE
LINE
LT1039A #2
RECEIVER
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
LOGIC
INPUT A
LT1039A #1
DRIVER
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 B
ON/OFF
(CHANNEL SELECT)
INPUT
6
LT1039A #2
DRIVER
LOGIC
INVERTER
1039A AI03
RS232
TRANSMISSION
LINE
For more information www.linear.com/1039
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