LTC491 Datasheet, PDF (1/12 Pages) Linear Technology – Differential Driver and Receiver Pair

FEATURES
s _{Low Power: ICC = 300µA Typical}
s _{Designed for RS485 or RS422 Applications}
s _{Single +5V Supply}
s _{–7V to +12V Bus Common Mode Range}
Permits ±7V Ground Difference Between Devices
on the Bus
s _{Thermal Shutdown Protection}
s _{Power-Up/Down Glitch-Free Driver Outputs Permit}
Live Insertion or Removal of Package
s _{Driver Maintains High Impedance in Three-State or}
with the Power Off
s _{Combined Impedance of a Driver Output and}
Receiver Allows up to 32 Transceivers on the Bus
s _{70mV Typical Input Hysteresis}
s _{28ns Typical Driver Propagation Delays with 5ns}
Skew
s _{Pin Compatible with the SN75180}
APPLICATI S
s _{Low Power RS485/RS422 Transceiver}
s _{Level Translator}
LTC491
Differential Driver and
Receiver Pair
DESCRIPTIO
The LTC491 is a low power differential bus/line transceiver
designed for multipoint data transmission standard RS485
applications with extended common mode range (+12V to
–7V). It also meets the requirements of RS422.
The CMOS design offers significant power savings over its
bipolar counterpart without sacrificing ruggedness against
overload or ESD damage.
The driver and receiver feature three-state outputs, with
the driver outputs maintaining high impedance over the
entire 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 receiver has a fail safe feature which guarantees a high
output state when the inputs are left open.
Both AC and DC specifications are guaranteed from 0°C to
70°C and 4.75V to 5.25V supply voltage range.
TYPICAL APPLICATI
DE
4
5
D
DRIVER
2
R
LTC491
RECEIVER
3
REB
9
120Ω
10
120Ω
4000 FT 24 GAUGE TWISTED PAIR
12
120Ω
11
120Ω
4000 FT 24 GAUGE TWISTED PAIR
DE
RECEIVER
R
LTC491
DRIVER
D
REB
LTC491 • TA01
1