LT1080/LT1081
Advanced Low Power
5V RS232 Dual Driver/Receiver
FEATURES
s
DESCRIPTIO
s
s
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s
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Superior to CMOS
– Improved Speed: Operates over 120kBaud
– Improved Protection: Outputs Can Be Forced
to
±30V
without Damage
– Three-State Outputs Are High
Impedance When Off
– Only Needs 1µF Capacitors
Absolutely No Latchup
CMOS Comparable Low Power: 60mW
Can Power Additional RS232 Drivers: 10mA
Supply Current in Shutdown: 1µA
Available in SO Package
Available with or without Shutdown
The LT
®
1080/LT1081 are the only dual RS232 driver/
receiver with charge pump to guarantee absolutely no
latchup. These interface optimized devices provide a real-
istic balance between CMOS levels of power dissipation
and real world requirements for ruggedness. The driver
outputs are fully protected against overload and can be
shorted to
±30V.
Unlike CMOS, the advanced architecture
of the LT1080/LT1081 does not load the signal line when
“shut down” or when power is off. Both the receiver and
RS232 outputs are put into a high impedance state. An
advanced output stage allows driving higher capacitive
loads at higher speeds with exceptional ruggedness
against ESD.
For applications requiring up to five drivers and five
receivers with charge pump in one package see the LT1130A
Series data sheet. A version of the LT1080/LT1081, the
LT1180A and LT1181A that use only 0.1µF capacitors, is
also available. All of Linear Technology’s RS232 ICs are
available in standard surface mount packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
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Portable Computers
Battery-Powered RS232 Systems
Power Supply Generator
Terminals
Modems
TYPICAL APPLICATIO
2
1µF
4
LT1080
5
1µF
6
12
LOGIC
INPUTS
15
7
17
3
5V INPUT
9V OUTPUT
1µF
–9V OUTPUT
Supply Generator Outputs
10
8
R
L
TO V
–
V
+
OUTPUT
R
L
TO GND
OUTPUT VOLTAGE (V)
1µF
RS232 OUTPUT
6
4
2
0
–2
–4
–6
V
CC
= 5V
11
13
8
14
5k
RS232 OUTPUT
RS232 INPUT
LOGIC
OUTPUTS
10
18
R
L
TO V
+
V
–
OUTPUT
0
2
4
9
5k
16
–8
RS232 INPUT
–10
ON/OFF
1080/81 • TA01
U
R
L
TO GND
6 8 10 12 14 16 18 20
OUTPUT CURRENT (mA)
1080/81 TA01a
U
U
1
LINER [ LINEAR TECHNOLOGY ]
