Datasheet

1
LTC1482
Low Power RS485 Transceiver
with Carrier Detect and
Receiver Fail-Safe
No Damage or Latchup to
±
15kV (Human Body
Model), IEC1000-4-2 Level 4 (
±
8kV) Contact and
Level 3 (
±
8kV) Air Discharge
Active Low Carrier Detect Output
Guaranteed High Receiver Output State for
Floating, Shorted or Terminated Inputs with
No Signal Present
Drives Low Cost Residential Telephone Wires
Low Power: I
CC
= 700µA Max with Driver Disabled
I
CC
= 900µA Max in Driver Mode Without Load
20µA Max Quiescent Current in Shutdown Mode
Single 5V Supply
7V to 12V Common Mode Range Permits ±7V
Ground Difference Between Devices on the Data Line
Maximum Data Rate of 4Mbps
Power Up/Down Glitch-Free Driver Outputs
Up to 32 Transceivers on the Bus
Available in 8-Lead MSOP, PDIP and SO Packages
The LTC
®
1482 is a low power RS485 compatible trans-
ceiver that offers an active low carrier detect output. The
open-drain carrier detect pin allows several transceivers
to share the same carrier detect line and can be used to
detect the insertion or removal of a driven RS485/RS422
cable.
Enhanced ESD protection allows the LTC1482 to with-
stand ±15kV (human body model), IEC-1000-4-2 level 4
(±8kV) contact and level 3 (±8kV) air discharge ESD
without latchup or damage.
The LTC1482 receiver stays alive at all times except in
shutdown. The supply current is a maximum of 700µA
and 900µA when the driver is disabled and enabled
respectively. In shutdown, the quiescent current of the
LTC1482 drops to a maximum of 20µA.
When the driver is disabled or the LTC1482 is in shut-
down, the driver outputs are three-stated and remain in
a high impedance state over the RS485 common mode
range.
Excessive power dissipation caused by bus contention or
faults is prevented by a thermal shutdown circuit, which
forces the driver outputs into a high impedance state.
The LTC1482 is fully specified over the commercial and
industrial temperature ranges and is available in 8-lead
MSOP, PDIP and SO packages.
Battery-Powered RS485/RS422 Applications
Low Power RS485/RS422 Transceiver
Level Translator
, LTC and LT are registered trademarks of Linear Technology Corporation.
RO1
CD1
DE1
DI1/SHDN1
R
V
CC1
LTC1482
GND1
B1
A1
B2
A2
120 120
D
V
CC2
GND2
1482 TA01
R
D
RO2
CD2
DE2
DI2/SHDN2
LTC1482
RS485 Interface
APPLICATIO S
U
FEATURES
TYPICAL APPLICATIO
U
DESCRIPTIO
U
Carrier Detect Output (2000 Foot STP Cable)
DE1 ↑↓ Dl1 = V
CC
1482 TA01a
DE2 = 0 Dl2 = V
CC
1k PULL-UP AT CD
DE1
A2
B2
CD2

Summary of content (16 pages)