Linear Technology LTC487 Manual

FEATURE S
■ Very Low Power: I = 110µA Typ
CC
Designed for RS485 or RS422 Applications
■
■ Single 5V Supply
– 7V to 12V Bus Common-Mode Range Permits ± 7V
■
GND Difference Between Devices on the Bus
■ Thermal Shutdown Protection
■ Power-Up/Down Glitch-Free Driver Outputs Permit
Live Insertion/Removal of Package
■ Driver Maintains High Impedance in Three-State or
with the Power Off
■ 28ns Typical Driver Propagation Delays with
5ns Skew
■ Pin Compatible with the SN75174, DS96174,
µA96174, and DS96F174
APPLICATI S
■ Low Power RS485/RS422 Drivers
■ Level Translator
TYPICAL APPLICATI
EN 12
4
2
1
120Ω
DI
DRIVER
3
1/4 LTC487
120Ω
4000 FT BELDEN 9841
DESCRIPTIO
®
The LTC487 is a low power differential bus/line driver
designed for multipoint data transmission standard RS485
Applications with extended common-mode range (– 7V to
12V). It also meets RS422 requirements.
The CMOS design offers significant power savings over its
bipolar counterpart without sacrificing ruggedness against
overload or ESD damage.
The driver features three-state outputs, with the driver
outputs maintaining high impedance over the entire com-
mon-mode range. Excessive power dissipation caused by
bus contention or faults is prevented by a thermal shut-
down circuit which forces the driver outputs into a high
impedance state.
Both AC and DC specifications are guaranteed from 0°C to
70°C (Commercial), – 40°C to 85°C (Industrial) and over
the 4.75V to 5.25V supply voltage range.
and LTC are registered trademarks and LT is a trademark of Linear Technology Corporation.
EN 12
4
2
3
RECEIVER RO
1
1/4 LTC489
LTC487 • TA01
LTC487
Quad Low Power
RS485 Driver
RS485 Cable Length Specification*
10k
1k
100
10
10k 100k 1M
DATA RATE (bps)
* APPLIES FOR 24 GAUGE, POLYETHYLENE
DIELECTRIC TWISTED PAIR
2.5M 10M
LTC487 • TA09
1