Datasheet

1
LTC1485
Differential Bus Transceiver
D
U
ESCRIPTIO
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, LTC and LT are registered trademarks of Linear Technology Corporation.
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A
O
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CA
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3
6
7
2
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120Ω
120Ω
DRIVER
RECEIVER
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3
4
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DI
2
1
6
7
4000 FT 24 GAUGE TWISTED PAIR
1485 TA01
LTC1485 LTC1485
RECEIVER
DRIVER
RE
RE
8
5V
8
5V
5
5
1
The LTC
®
1485 is a low power differential bus/line trans-
ceiver 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 with Schottky 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. I/O pins are protected against
multiple ESD strikes of over ±10kV.
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 – 40°C
to 85°C and 4.75V to 5.25V supply voltage range.
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Low Power RS485/RS422 Transceiver
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Level Translator
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ESD Protection over ± 10kV
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Low Power: I
CC
= 1.8mA Typ
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28ns Typical Driver Propagation Delays with
4ns Skew
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Designed for RS485 or RS422 Applications
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Single 5V Supply
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–7V to 12V Bus Common-Mode Range Permits ±7V
Ground Difference Between Devices on the Bus
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Thermal Shutdown Protection
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Power-Up/Down Glitch-Free Driver Outputs
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Driver Maintains High Impedance in Three-State or
with the Power Off
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Combined Impedance of a Driver Output and
Receiver Allows up to 32 Transceivers on the Bus
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60mV Typical Input Hysteresis
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Pin Compatible with the SN75176A, DS75176A, and
SN75LBC176