LTC1321 Datasheet, PDF (1/20 Pages) Linear Technology – RS232/EIA562/RS485 Transceivers

LTC1321/LTC1322/LTC1335
RS232/EIA562/RS485
Transceivers
FEATURES
s _{LTC1321: 2-EIA562/RS232 Transceivers/2-RS485}
Transceivers
s _{LTC1322: 4-EIA562/RS232 Transceivers/2-RS485}
Transceivers
s _{LTC1335: 4-EIA562 Transceivers/2-RS485}
Transceivers with OE
s _{LTC1321/LTC1322 Have the Same Pinout as}
SP301/SP302
s _{LTC1335 Features Receiver Three-State Outputs}
s _{Low Supply Current: 1mA Typical}
s _{15µA Supply Current in Shutdown}
s _{120kBaud in EIA/TIA-562 or RS232 Mode}
s _{10MBaud in RS485/RS422 Mode}
s _{Self-Testing Capability in Loopback Mode}
s _{Power-Up/Down Glitch-Free Outputs}
s _{Driver Maintains High Impedance in Three-State,}
Shutdown or With Power Off
s _{Thermal Shutdown Protection}
s _{I/O Lines Can Withstand ±25V}
s _{Withstands Repeated 10kV ESD Pulses}
U
APPLICATIONS
s _{Low Power RS485/RS422/EIA562/RS232 Interface}
s _{Cable Repeater}
s _{Level Translator}
DESCRIPTIO
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.
TYPICAL APPLICATI
V_CC1
24
5V
1
22
RX OUT
DR ENABLE ²¹
20
DR IN
5V ¹⁹
5V ¹⁸
17
DR IN
16
DR IN
15
RX OUT
14
RX OUT
13
V_EE1
–5V
LTC1322
2
3
4
5
6 _5V
7 _0V
8
9
10
11
12
120Ω
RS485 INTERFACE
120Ω
4000-FT 24-GAUGE TWISTED PAIR
EIA562 INTERFACE
11
10
9
8
7
5V
0V ⁶
3
2
5
4
12
LTC1322
24
1
15
RX OUT
V_CC2
5V
16
DR ENABLE
17 _{DR IN}
19 _5V
18 _5V
22 _{RX OUT}
23 _{RX OUT}
20
DR IN
21
DR IN
13
V_EE2
–5V
1321/22/35 TA01
1