LTC1338
5V Low Power RS232
5-Driver/3-Receiver Transceiver
FEATURES
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DESCRIPTIO
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Low Supply Current: 500µA
0.2µA Supply Current in SHUTDOWN
50µA Supply Current in RECEIVER ALIVE Mode
ESD Protection Over
±10kV
Operates from a Single 5V Supply
Uses Small Capacitors: 0.1µF
Operates to 120k Baud
Three-State Outputs Are High Impedance When Off
Output Overvoltage Does Not Force Current
Back into Supplies
RS232 I/O Lines Can Be Forced to
±25V
Without Damage
Flowthrough Architecture
The LTC1338 is a 5-driver/ 3-receiver RS232 trans-
ceiver with very low supply current. In the no load
condition, the supply current is only 500µA. The charge
pump only requires four 0.1µF capacitors.
In SHUTDOWN mode, the supply current is further
reduced to 0.2µA. In RECEIVER ALIVE mode, all three
receivers are kept alive and the supply current is 50µA.
All RS232 outputs assume a high impedance state in
SHUTDOWN and with the power off.
The LTC1338 is fully compliant with all data rate and
overvoltage RS232 specifications. The transceiver can
operate up to 120k baud with a 2500pF, 3kΩ load. Both
driver outputs and receiver inputs can be forced to
±25V
without damage, and can survive multiple
±10kV
ESD strikes.
APPLICATI
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Battery-Powered Modems
Battery-Powered DCE
Notebook Computers
Palmtop Computers
TYPICAL APPLICATI
V
+
C1
0.1µF
C2
0.1µF
DRIVER 1 OUT
DRIVER 2 OUT
RX1 IN
DRIVER 3 OUT
RX2 IN
DRIVER 4 OUT
RX3 IN
DRIVER 5 OUT
RX ENABLE
NC
V
CC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
5-Drivers/3-Receivers with SHUTDOWN
28
LTC1338
27
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25
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23
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20
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16
15
C3
0.1µF
DRIVER 1 IN
DRIVER 2 IN
RX1 OUT
DRIVER 3 IN
RX2 OUT
DRIVER 4 IN
RX3 OUT
DRIVER 5 IN
GND
DRIVER ENABLE
NC
LTC1338 • TA01
V
–
C4
0.1µF
1200
1000
QUIESCENT CURRENT (µA)
800
600
400
200
0
–40
SHUTDOWN
CURRENT
QUIESCENT
CURRENT
–20
TEST CONDITION:
V
CC
= 5V, ALL DRIVER INPUTS TIED TO V
CC
.
U
Supply Current
1.2
1.0
SHUTDOWN CURRENT (µA)
UO
UO
0.8
0.6
0.4
0.2
0
100
0
20
40
60
TEMPERATURE (°C)
80
LTC1338 • TA02
1
LINER [ LINEAR TECHNOLOGY ]
