UM3087E Datasheet, PDF (1/13 Pages) Union Semiconductor, Inc. – ±15kV ESD-Protected, Fail-Safe, Hot-Swappable

UM3087E
±15kV ESD-Protected, Fail-Safe, Hot-Swappable
Auto Polarity Reversal RS-485 Transceivers
UM3087E SOP8/DIP8
General Description
The UM3087E series are +5.0V powered ±15kV ESD protected, fail-safe, hot-swappable, auto
polarity reversal RS-485 transceivers. The device includes fail-safe circuitry, which guarantees a
logic-high receiver output when the receiver inputs are open, shorted or idle. This means that the
receiver output will be logic high if all transmitters on a terminated bus are disabled (high
impedance). The UM3087E features reduced slew-rate driver that minimizes EMI and reduces
reflections caused by improperly terminated cables, allowing error-free data transmission up to
500kbps. All transmitter outputs and receiver inputs are protected to ±15kV using the Human
Body Model and IEC61000-4-2, Air-Gap Discharge.
The UM3087E includes cable auto-invert functions that reverse the polarity of the RS485 bus pins
in case the cable is misconnected. Receiver’s full fail-safe features are maintained even when the
receiver polarity has been reversed.
The transceivers typically draw 300μA of supply current when unloaded, or when fully loaded
with the drivers disabled. The device has a 1/8-unit-load receiver input impedance that allows up
to 256 transceivers on the bus and is intended for half-duplex communications.
Applications
Features
 Smart Meters/Automated Meter
 Automatic Polarity Reversal RS-485
Reading Systems
Transceivers
 Industrial-Control Local Area
 I/O logic compatible with +5V, +3.3V &
Networks
+1.8V logic
 PROFIBUS® and Other RS-485 Based  ESD Protection for RS-485 I/O Pins
Field Bus Networks
±15kV—IEC61000-4-2, Air-Gap Discharge
 Building Lighting and Environmental
±8kV—IEC61000-4-2, Contact Discharge
Control Systems
 True Fail-Safe Receiver
 Transceivers for EMI-Sensitive
 Enhanced Slew-Rate Limiting
Applications
 Allows up to 256 Transceivers on the Bus
 Thermal Shutdown
 Current-Limiting for Driver Overload
Protection
Pin Configurations
Top View
RO
VCC
RE
L1
DE
L2
DI
GND
XXXXXX
XXXX
XX
Ordering Information
Part Number
Marking Code
UM3087EESA
UM3087EESA
UM3087EEPA
UM3087EEPA
Operating Temperature
-40°C to +85°C
-40°C to +85°C
Package Type
SOP8
DIP8
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http://www.union-ic.com Rev.02 Jan.2014
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