LTC1321/LTC1322/LTC1335
RS232/EIA562/RS485
Transceivers
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DESCRIPTIO
FEATURES
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LTC1321: 2-EIA562/RS232 Transceivers/2-RS485
Transceivers
LTC1322: 4-EIA562/RS232 Transceivers/2-RS485
Transceivers
LTC1335: 4-EIA562 Transceivers/2-RS485
Transceivers with OE
LTC1321/LTC1322 Have the Same Pinout as
SP301/SP302
LTC1335 Features Receiver Three-State Outputs
Low Supply Current: 1mA Typical
15µA Supply Current in Shutdown
120kBaud in EIA/TIA-562 or RS232 Mode
10MBaud in RS485/RS422 Mode
Self-Testing Capability in Loopback Mode
Power-Up/Down Glitch-Free Outputs
Driver Maintains High Impedance in Three-State,
Shutdown or With Power Off
Thermal Shutdown Protection
I/O Lines Can Withstand ±25V
Withstands Repeated 10kV ESD Pulses
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APPLICATIONS
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Low Power RS485/RS422/EIA562/RS232 Interface
Cable Repeater
Level Translator
The RS232/EIA562 transceivers operate to 120kbaud and
are in full compliance with EIA/TIA-562 specification. The
RS485 transceivers operate to 10Mbaud and are in full
compliance with RS485 and RS422 specifications. All
interface drivers feature short-circuit and thermal shutdown protection. An enable pin allows RS485 driver
outputs to be forced into high impedance which is maintained even when the outputs are forced beyond supply
rails or power is off. Both driver outputs and receiver
inputs feature ±10kV ESD protection. A loopback mode
connects the driver outputs back to the receiver inputs for
diagnostic self-test.
The LTC1321/LTC1322 can support RS232 voltage levels
when 6.5V ≤ VDD ≤ 10V and – 6.5V ≥ VEE ≥ – 10V. The
LTC1335 supports receiver output enable but not RS232
levels. A shutdown mode reduces the ICC supply current
to 15µA.
UO
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The LTC1321/LTC1322/LTC1335 are low power CMOS
bidirectional transceivers, each featuring two reconfigurable
interface ports. Each can be configured as two RS485
differential ports, as two single-ended ports, or as one
RS485 differential port and one single-ended port. The
LTC1321/LTC1322 can provide RS232 or EIA562 compatible single-ended outputs; the LTC1335 provides EIA562
compatible outputs and additionally includes an output
enable pin, allowing the receiver logic level outputs to be
three-stated.
TYPICAL APPLICATI
VCC1
5V
RX OUT
DR ENABLE
DR IN
5V
5V
DR IN
DR IN
RX OUT
RX OUT
VEE1
–5V
24
1
22
2
3
RS485 INTERFACE
21
120Ω
120Ω
9
5
19
18
16
4
20
8
6
LTC1322
24
1
15
11
10
7
17
8
16
9
4000-FT 24-GAUGE TWISTED PAIR
5V
5V
0V
0V
EIA562 INTERFACE
17
7
6
19
LTC1322
18
3
22
2
23
15
10
5
20
14
11
4
21
13
12
12
13
VCC2
5V
RX OUT
DR ENABLE
DR IN
5V
5V
RX OUT
RX OUT
DR IN
DR IN
VEE2
–5V
1321/22/35 TA01
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