LTC1484
Low Power
RS485 Transceiver
with Receiver Fail-Safe
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DESCRIPTIO
FEATURES
The LTC®1484 is a low power RS485 compatible trans-
ceiver. Inreceivermode, itoffersafail-safefeaturewhich
guarantees a high receiver output state when the inputs
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No Damage or Latchup to
Body Model), IEC-1000-4-2 Level 4 Contact (±8kV)
±
15kV ESD (Human
and Level 3 (±8kV) Air Gap Specifications
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Guaranteed High Receiver Output State for Floating, are left open, shorted together or terminated with no
Shorted or Terminated Inputs with No Signal
Present
Drives Low Cost Residential Telephone Wires
Low Power: ICC = 700µA Max with Driver Disabled
ICC = 900µA Max for Driver Enable with No 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
Power Up/Down Glitch-Free Driver Outputs
Up to 32 Transceivers on the Bus
signal present. No external components are required to
ensure the high receiver output state.
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Both driver and receiver feature three-state outputs with
separate receiver and driver control pins. The driver
outputs maintain high impedance over the entire com-
mon mode range when three-stated. Excessive power
dissipation caused by bus contention or faults is pre-
vented by a thermal shutdown circuit that forces the
driver outputs into a high impedance state.
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Enhanced ESD protection allows the LTC1484 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.
Pin Compatible with the LTC485
Available in 8-Lead MSOP, PDIP and SO Packages
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The LTC1484 is fully specified over the commercial and
industrial temperature ranges and is available in 8-lead
MSOP, PDIP and SO packages.
APPLICATIO S
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Battery-Powered RS485/RS422 Applications
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Low Power RS485/RS422 Transceiver
, LTC and LT are registered trademarks of Linear Technology Corporation.
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Level Translator
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TYPICAL APPLICATIO
Driving a 2000 Foot STP Cable
RS485 Interface
Dl1
LTC1484
R
LTC1484
RO2
RE2
DE2
DI2
RO1
RE1
DE1
DI1
V
V
CC2
CC1
B1
A1
B2
A2
R
B2
A2
120Ω
GND1
120Ω
D
D
GND2
RO2
1484 TA01
Dl1 ↑↓
Dl2 = 0
DE1 = VCC
DE2 = 0
1484 TA01a
RE1 = RE2 = 0
1