LTC1321/LTC1322/LTC1335
RS232/EIA562/RS485
Transceivers
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DESCRIPTIO
EATURE
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F
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The LTC1321/LTC1322/LTC1335 are low power CMOS
bidirectionaltransceivers,eachfeaturingtworeconfigurable
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/LTC1322canprovideRS232orEIA562compat-
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.
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
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LTC1321/LTC1322 Have the Same Pinout as
SP301/SP302
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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
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.
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Thermal Shutdown Protection
I/O Lines Can Withstand ±25V
Withstands Repeated 10kV ESD Pulses
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APPLICATIONS
Low Power RS485/RS422/EIA562/RS232 Interface
Cable Repeater
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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.
Level Translator
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O
TYPICAL APPLICATI
24
1
15
V
24
1
V
CC2
CC1
5V
5V
11
10
2
3
22
RS485 INTERFACE
RX OUT
RX OUT
21
20
16
17
120Ω
DR ENABLE
120Ω
DR ENABLE
DR IN
9
4
DR IN
8
7
5
4000-FT 24-GAUGE TWISTED PAIR
EIA562 INTERFACE
19
18
22
23
20
21
13
19
18
17
16
15
14
13
6
5V
5V
5V
0V
5V
5V
5V
0V
LTC1322
6
LTC1322
7
3
2
8
RX OUT
RX OUT
DR IN
DR IN
DR IN
RX OUT
RX OUT
9
5
10
11
4
DR IN
12
12
V
V
EE2
EE1
–5V
–5V
1321/22/35 TA01
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