LTC1484_15 Datasheet, PDF (1/16 Pages) Linear Technology – Low Power RS485 Transceiver with Receiver Fail-Safe

LTC1484
Low Power
RS485 Transceiver
with Receiver Fail-Safe
FEATURES
s _{No Damage or Latchup to ±15kV ESD (Human}
Body Model), IEC-1000-4-2 Level 4 Contact (±8kV)
and Level 3 (±8kV) Air Gap Specifications
s _{Guaranteed High Receiver Output State for Floating,}
Shorted or Terminated Inputs with No Signal
Present
s _{Drives Low Cost Residential Telephone Wires}
s _{Low Power: ICC = 700µA Max with Driver Disabled}
s _{ICC = 900µA Max for Driver Enable with No Load}
s _{20µA Max Quiescent Current in Shutdown Mode}
s _{Single 5V Supply}
s _{– 7V to 12V Common Mode Range Permits ±7V}
Ground Difference Between Devices on the Data Line
s _{Power Up/Down Glitch-Free Driver Outputs}
s _{Up to 32 Transceivers on the Bus}
s _{Pin Compatible with the LTC485}
s _{Available in 8-Lead MSOP, PDIP and SO Packages}
U
APPLICATIO S
s _{Battery-Powered RS485/RS422 Applications}
s _{Low Power RS485/RS422 Transceiver}
s _{Level Translator}
DESCRIPTIO
The LTC^®1484 is a low power RS485 compatible trans-
ceiver. In receiver mode, it offers a fail-safe feature which
guarantees a high receiver output state when the inputs
are left open, shorted together or terminated with no
signal present. No external components are required to
ensure the high receiver output state.
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.
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.
The LTC1484 is fully specified over the commercial and
industrial temperature ranges and is available in 8-lead
MSOP, PDIP and SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
RS485 Interface
LTC1484
LTC1484
RO1
V_CC1
V_CC2
RO2
RE1
R
B1
B2
R
RE2
DE1
A1
120Ω
120Ω _A2
DE2
D
D
DI1
GND1
GND2
DI2
1484 TA01
Driving a 2000 Foot STP Cable
Dl1
B2
A2
RO2
Dl1 ↑↓
Dl2 = 0
RE1 = RE2 = 0
DE1 = V_CC
DE2 = 0
1484 TA01a
1