LTC1321/LTC1322/LTC1335
RS232/EIA562/RS485
Transceivers
FEATURES
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s
DESCRIPTIO
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s
s
s
s
s
s
s
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s
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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
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 compat-
ible 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.
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 shut-
down protection. An enable pin allows RS485 driver
outputs to be forced into high impedance which is main-
tained 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
≤
V
DD
≤
10V and – 6.5V
≥
V
EE
≥
– 10V. The
LTC1335 supports receiver output enable but not RS232
levels. A shutdown mode reduces the I
CC
supply current
to 15µA.
APPLICATIONS
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Low Power RS485/RS422/EIA562/RS232 Interface
Cable Repeater
Level Translator
TYPICAL APPLICATI
V
CC1
5V
RX OUT
DR ENABLE
DR IN
5V
5V
DR IN
DR IN
RX OUT
RX OUT
V
EE1
–5V
24
1
22
21
20
19
18
17
16
15
14
13
2
3
120Ω
4
5
6
LTC1322
7
8
9
10
11
12
5V
0V
RS485 INTERFACE
120Ω
11
10
9
8
5V
7
6
3
2
5
4
12
LTC1322
4000-FT 24-GAUGE TWISTED PAIR
EIA562 INTERFACE
0V
U
24
1
15
16
17
19
18
22
23
20
21
13
V
CC2
5V
RX OUT
DR ENABLE
DR IN
5V
5V
RX OUT
RX OUT
DR IN
DR IN
V
EE2
–5V
1321/22/35 TA01
UO
U
1
LINER [ LINEAR TECHNOLOGY ]
