LTC1348 Datasheet, PDF (1/8 Pages) Linear Technology – 3.3V/5V Low Power RS232 3-Driver/5-Receiver Transceiver

LTC1348
3.3V/5V Low Power RS232
3-Driver/5-Receiver Transceiver
FEATURES
s _{Low Supply Current: 600µA at 3.3V}
s _{Supply Current in Shutdown: 0.2µA}
s _{Supply Current in Receiver Alive Mode: 15µA}
s _{ESD Protection over ±10kV}
s _{Operates from a Single 3V to 5.5V Supply}
s _{Operates to 120kBaud with 0.1µF Flying Capacitors}
s _{Three-State Outputs Are High Impedance When Off}
s _{Output Overvoltage Does Not Force Current}
Back into Supplies
s _{RS232 I/O Lines Can Be Forced to ±25V}
Without Damage
s _{Flowthrough Architecture}
APPLICATI S
s _{Notebook Computers}
s _{Palmtop Computers}
s _Printers
s _{Portable Instruments}
DESCRIPTIO
The LTC^®1348 is a 3-driver/5-receiver RS232 transceiver
with very low supply current. The charge pump only
requires five 0.1µF capacitors. The LTC1348 provides full
RS232 output levels when operated over a wide supply
range of 3V to 5.5V
The transceiver operates in one of four modes: Normal,
Receiver Disable, Receiver Alive and Shutdown. In Normal
or Receiver Disable mode, I_CC is only 600µA at 3.3V and
800µA at 5V in the no load condition. In Shutdown mode,
the supply current is further reduced to 0.2µA. In Receiver
Alive mode, all five receivers are kept alive and the supply
current is 15µA. All RS232 outputs assume a high imped-
ance state in Shutdown or Receiver Alive mode or with the
power off. The receiver outputs assume a high impedance
state in Receiver Disable or with the power off.
The LTC1348 is fully compliant with all data rate and
overvoltage RS232 specifications. The transceiver oper-
ates up to 120kbaud with all drivers loaded with 1000pF,
3kΩ. Both driver outputs and receiver inputs can be forced
to ±25V without damage and can survive multiple ±10kV
ESD strikes.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATI
3-Drivers/5-Receivers with Shutdown
C5
0.1µF
V⁺ 1
2
C2
0.1µF
3
4
V_{CC 5}
C1
0.1µF
6
DR 1 OUT ⁷
RX1 IN ⁸
DR 2 OUT ⁹
RX2 IN ¹⁰
RX3 IN ¹¹
RX4 IN ¹²
DR 3 OUT ¹³
RX5 IN ¹⁴
LTC1348
28 V^–
27
26
C3
0.1µF
25 _{DR 1 IN}
24
RX1 OUT
23
DR 2 IN
22
RX2 OUT
21 _{RX3 OUT}
20
RX4 OUT
19
DR 3 IN
18 _{RX5 OUT}
17 _DREN
16
RXEN
15
GND
LT1348 • TA01
C4
0.1µF
Supply Current
1.6
1.6
1.4
1.4
1.2
QUIESCENT
1.2
1.0
CURRENT
1.0
V_CC = 5V
0.8
0.8
V_CC = 3.3V
0.6
0.6
SHUTDOWN
0.4
V_CC = 3.3V CURRENT
0.4
OR 5V
0.2
0.2
0
–40 –20
0 20 40 60
TEMPERATURE (˚C)
0
80
LT1348 •TA02
1