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Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510)6687000 • Fax (510)668-7017 • www.exar.com SP4082E_100_122007
DESCRIPTION
FEATURES
APPLICATIONS
SP4082E
5V RS-485/RS-422 Transceivers
1/8th Unit Load, Slew-Rate Limited, ±15kV ESD-Protected
• 5.0V single supply operation
• Receiver failsafe on open or shorted lines
• 1/8th Unit Load, 256 transceivers on bus
• Robust ESD protection for RS-485 pins
±15kV Human Body Model
• Controlled driver slew rates
115kbps, Low EMI
•Driver short circuit current limit and
thermal shutdown for overload protection
•Industry standard package footprints
• Motor Control
• Building Automation
• Security Systems
• Remote Meter Reading
• Long or un-terminated transmission lines
The SP4082E is designed for reliable, bidirectional communication on multipoint bus transmission
lines. The device contains one differential driver and one differential receiver. It is a half-duplex de-
vice. The device complys with TIA/EIA-485 and TIA/EIA-422 standards. Lead-free and RoHS compli-
ant packages are available.
This device is ruggedized for use in harsh operating conditions over the entire common-mode volt-
age range from -7V to +12V. Receivers are specially designed to fail-safe to a logic high output state
if the inputs are un-driven or shorted. All RS-485 bus-pins are protected against severe ESD events
up to ±15kV (Human Body Model). Drivers are protected from excess current ow caused by bus
contention or output short-circuits by both an internal current limit and a thermal-overload shutdown.
Devices are rated for industrial (-40 to +85ºC) operating temperatures. Receivers have exceptionally
high input impedance, which places only 1/8th the standard load on a shared bus. Up to 256 trans-
ceivers may coexist while preserving full signal margin.
The device operates from a single 5.0V power supply and draws negligible quiescent power. The
device has an independent enable and disable for the driver and receiver and will enter a low power
shutdown mode if both driver and receiver are disabled. All outputs maintain high impedance during
shutdown or when powered-off.
8 PIN NSOIC
SP4082E
Half Duplex
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3
4
5
6
7
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GND
A
B
Vcc
RO
RE
DE
DI
