XR3070-78X Datasheet, PDF (1/24 Pages) Exar Corporation – LOW POWER 18V TOLERANT RS-485/RS-422 +3.3V TRANSCEIVERS

XR3070-78X
LOW POWER 18V TOLERANT RS-485/RS-422 +3.3V TRANSCEIVERS
MAY 2015
REV. 1.0.2
GENERAL DESCRIPTION
FEATURES
The XR3070-78X family of high performance RS-485/
422 devices are designed for improved performance in
noisy industrial environments and increased tolerance
to system faults.
The analog bus pins can withstand direct shorts up to
±18V, and are protected against ESD events up to
±15kV. The differential high output driver delivers 10%
higher SNR than standard RS-485/422 devices, afford-
ing additional noise margin or extended cable lengths.
The receivers include full fail-safe circuitry, guarantee-
ing a logic-high receiver output when the receiver
inputs are open, shorted, or undriven. The receiver
input impedance is at minimum 96kW (1/8 unit load),
allowing up to 256 devices on the bus while preserving
the full signal margin.
The drivers are protected by short circuit detection as
well as thermal shutdown, and maintain high imped-
ance in shutdown or when powered off. The XR3070-
75X drivers are slew limited for reduced EMI and error-
free communication over long or unterminated data
cables.
The devices with DE and RE pins include hot swap cir-
cuitry to prevent false transitions on the bus during
powerup or live insertion, and can enter a 1nA low cur-
rent shutdown mode for extreme power savings.
 10% Higher SNR (Signal-to-Noise Ratio)
compared to other RS-485 devices (1.65V vs. 1.5V)
 ±18V Fault Tolerance on Analog Bus pins
 Robust ESD (ElectroStatic Discharge) Protection:
±15kV IEC 61000-4-2 Air Gap Discharge
± 8kV IEC 61000-4-2 Contact Discharge
±15kV Human Body Model
± 4kV Human Body Model on non-bus pins
 +3.0V to +3.6V Operation (3.3V ± 10%)
 300μA Idle Current, 1nA Shutdown Current
 Enhanced Receiver Fail-Safe Protection for Open,
Shorted, or Terminated but Idle Data Lines
 Hot-Swap Glitch Protection on DE and RE Pins
 Driver Short Circuit Current Limit and Thermal
Shutdown for Overload Protection
 1/8^th Unit Load Allows up to 256 Devices on Bus
 Operating Temperature Range:
Industrial -40°C to 85°C
Extended -40°C to 125°C
 Industry Standard 8 and 14 NSOIC Packages
The transceivers draw less than 600μA from a +3.3V
supply, and typically only 300μA when idling with the
receivers active.
RO 1
R
8 V_CC
RE 2
7 B/Z
DE 3
6 A/Y
DI 4
D
5 GND
TYPICAL APPLICATIONS
 Motor Control
 Security Systems
 Building and Process Automation
 Remote Utility Meter Reading
 Energy Monitoring and Control
 Long or Unterminated Transmission Lines
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • [phone] • FAX [phone] • www.exar.com