LTC1480
3.3V Ultra-Low Power
RS485 Transceiver
FEATURES
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DESCRIPTIO
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True RS485 from a Single 3.3V Supply
Low Power: I
CC
= 500µA Max with Driver Disabled
I
CC
= 600
µ
A Max with Driver Enabled, No Load
1
µ
A Quiescent in Shutdown Mode
ESD Protection to
±
10kV on Receiver Inputs and
Driver Outputs
–7V to 12V Common-Mode Range Permits
±7V
Ground Difference Between Devices on the Data Line
Thermal Shutdown Protection
Power Up/Down Glitch-Free Driver Outputs Permit
Live Insertion or Removal of Transceiver
Driver Maintains High Impedance in Three-State or
with the Power Off
Up to 32 Transceivers on the Bus
50ns Typical Driver Propagation Delays with
10ns Skew
Pin Compatible with the LTC485
The LTC
®
1480 is an ultra-low power differential line trans-
ceiver which provides full RS485 compatibility while oper-
ating from a single 3.3V supply. It is designed for data
transmission standard RS485 applications with extended
common-mode range (12V to –7V). It also meets the
requirements of RS422 and features high speed operation
up to 2.5Mb/s. The CMOS design offers significant power
savings without sacrificing ruggedness against overload
or ESD damage. Typical quiescent current is only 300µA
while operating and 1µA in shutdown.
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. I/O pins are protected against multiple
ESD strikes of up to
±10kV.
The LTC1480 is fully specified over the commercial and
extended industrial temperature range. The LTC1480 is
available in 8-pin SO and DIP packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATI
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Battery-Powered RS485/RS422 Applications
Low Power RS485/RS422 Transceiver
Level Translator
TYPICAL APPLICATI
3.3V
LTC1480
RO 1
RE
DE
D1
2
3
4
D
R
8
7
6
5
B
120Ω
A
3.3V RS485 Network
3.3V
LTC1480
SHIELD
SHIELD
B
120Ω
A
3.3V
8
B
7
A
6
5
6
5
D
3
4
8
7
R
1 RO
OUTPUT VOLTAGE (V)
2
RE
DE
D1
R
1
RO
2
RE
3
LTC1480
D
4
DE D1
LTC1480 • TA01
U
Driver Differential
Output Voltage vs Output Current
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
10
20 30 40 50 60 70
OUTPUT CURRENT (mA)
80
90
V
CC
= 3.3V
T
A
= 25°C
LTC1480 • TA02
UO
UO
1
LINER [ LINEAR TECHNOLOGY ]
