Datasheet

6
LT1039/LT1039-16
1039fd
APPLICATIONS INFORMATION
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The driver output stage of the LT1039 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.
LT1039 Driver
Some drivers have diodes connected between the out-
puts and the supplies, so externally applied voltages can
cause excessive supply voltage to develop
LT1039 #1
DRIVER
LT1039 #2
DRIVER
LOGIC
INPUT A
LOGIC
INPUT B
1039 AI03
ON/OFF
(CHANNEL SELECT)
INPUT
LOGIC
INVERTER
RS232
TRANSMISSION
LINE
Sharing a Receiver Line
WITH SOME DRIVERS,
EXTERNALLY APPLIED
VOLTAGE CAN FORCE
THE SUPPLIES
1039 AI02
V
+
V
–
Older RS232 Drivers and Other CMOS Drivers
Sharing a Transmitter Line
Placing the LT1039 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.
–30V
30V
OUTPUT CAN
BE FORCED
EXTERNALLY
1039 AI01
LT1039
Transceiver
LT1039 #1
RECEIVER
RS232
INPUT A
RS232
INPUT B
1039 AI04
ON/OFF
(CHANNEL SELECT)
INPUT
LOGIC
INVERTER
LOGIC
OUTPUT
LT1039 #2
RECEIVER
LT1039 #1
DRIVER
LOGIC
TRANSMIT/RECEIVE
LINE
RS232
TRANSMIT/RECEIVE
LINE
1039 AI05
ON/OFF
(TRANSMIT/RECEIVE)
INPUT
LOGIC
INVERTER
LT1039 #2
RECEIVER
The shutdown mode also drops all supply currents (V
CC
,
V
+
, V
–
) to zero for power conscious systems.