LT1180A/LT1181A
Low Power 5V RS232
Dual Driver/Receiver with
0.1µF Capacitors
U
DESCRIPTIO
FEATURES
ESD Protection over ±10kV
The LT®1180A/LT1181A are dual RS232 driver/receiver
pairs with integral charge pump to generate RS232 volt-
age levels from a single 5V supply. These circuits feature
rugged bipolar design to provide operating fault tolerance
and ESD protection unmatched by competing CMOS
designs. Using only 0.1µF external capacitors, these cir-
cuits consume only 40mW of power, and can operate to
120k baud even while driving heavy capacitive loads. New
ESDstructuresonthechipallowtheLT1180A/LT1181Ato
survive multiple ±10kV strikes, eliminating the need for
costly TransZorbs® on the RS232 line pins. The LT1180A/
LT1181A are fully compliant with EIA RS232 standards.
Driver outputs are protected from overload, and can be
shorted to ground or up to ±30V without damage. During
shutdown or power-off conditions, driver and receiver
outputs are in a high impedance state, allowing line
sharing.
■
■
Uses Small Capacitors: 0.1µF
■
120kBaud Operation for RL = 3k, CL = 2500pF
■
250kBaud Operation for RL = 3k, CL = 1000pF
■
Outputs Withstand ±30V Without Damage
■
CMOS Comparable Low Power: 40mW
■
Operates from a Single 5V Supply
Rugged Bipolar Design
■
■
Outputs Assume a High Impedance State When Off
or Powered Down
Meets All RS232 Specifications
Available With or Without Shutdown
Absolutely No Latch-up
Available in SO PUackage
■
■
■
■
APPLICATIO S
■
■
Portable Computers
Battery-Powered Systems
Power Supply Generator
Terminals
The LT1181A is available in 16-pin DIP and SO packages.
The LT1180A is supplied in 18-pin DIP and SO packages
for applications which require shutdown.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TransZorb is a registered trademark of General Instruments, GSI
■
■
■
Modems
U
TYPICAL APPLICATIO
2
17
Output Waveforms
5V INPUT
+
+
0.1µF
4
3
V
OUT
+
+
0.1µF
0.1µF
LT1180A
DRIVER
OUTPUT
5
7
–
RL = 3k
V
OUT
+
CL = 2500pF
0.1µF
6
12
15
RS232 OUTPUT
RECEIVER
LOGIC
INPUTS
OUTPUT
R
CL = 50pF
11
13
8
RS232 OUTPUT
RS232 INPUT
14
INPUT
5k
5k
LOGIC
OUTPUTS
10
18
9
RS232 INPUT
LT1180A • TA02
16
ON/OFF
LT1180A • TA01
11801afb
1