XR3170E-3178E th 3.3V HIGH SPEED RS-485/RS-422 TRANSCEIVERS WITH 1/8 UNIT LOAD DECEMBER 2009 REV. 1.0.0 GENERAL DESCRIPTION FEATURES The XR3170E - XR3178E family of RS-485 devices 3.3V Single Supply Operation are designed for reliable, bidirectional communication High Speed 20Mbps Data Rate on multipoint bus transmission lines. Each device contains one differential driver and one differential Slew Rate Limited - 250kbps And 500kbps Data receiver. XR3172E, XR3175E and XR3178E are half- Rate duplex devices other part numbers are full-duplex. th 1/8 Unit Load, 256 Transceivers On Bus All devices comply with TIA/EIA-485 and TIA/EIA-422 standards. Lead free and RoHS compliant packages Enhanced Failsafe For Receiver - Open, Short Or are available for all models. Terminated Lines These devices are ruggedized for use in harsh Robust ESD Protection For RS-485 Pins operating conditions over the entire common-mode +/-15kV Air-Gap Discharge voltage range from -7V to +12V. Receivers are +/-15kV Human Body Model specially designed to fail-safe to a logic high output state if the inputs are left un-driven or shorted. All RS- +/-8kV Contact Discharge 485 bus pins are protected against severe ESD Hot Swap Glitch Protection events up to +/-15kV (Air-Gap and Human Body Model) and up to +/-8kV Contact Discharge (IEC Driver Short Circuit Current Limit And Thermal 61000-4-2). Drivers are protected from excess Shutdown For Overload Protection current flow caused by bus contention or output Ultra-Low 650uA Quiescent Current short-circuits by both an internal current limit and a thermal-overload shutdown. Devices are rated for 1A Shutdown Mode Industrial (-40 to +85C) operating temperatures. Industry Standard Package Footprints Receivers have exceptionally high input impedance, th which places only 1/8 the standard load on a shared TYPICAL APPLICATIONS bus. Up to 256 transceivers may coexist while preserving full signal margin. Motor Control All devices operate from a single 3.3V power supply Building Automation and draw negligible quiescent power. All versions Security Systems except the XR3171E, XR3174E and XR3177E may independently enable and disable their driver and Remote Utility Meter Reading receiver and enter a low power shutdown mode if Long Or Un-Terminated Transmission Lines both driver and receiver are disabled. All outputs maintain high impedance in shutdown or when powered off. FIGURE 1. TYPICAL APPLICATION CIRCUIT DE DE XR3178E XR3178E B B DI DI STUB R R T T A A RO RO BBAA RE RE DE DE RE RE DI RO DI RO Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com XR3178E XR3178EXR3170E-3178E th 3.3V HIGH SPEED RS-485/RS-422 TRANSCEIVERS WITH 1/8 UNIT LOAD REV. 1.0.0 FIGURE 2. PIN OUT ASSIGNMENT RO 1 8 VCC 8-Pin NSOIC Half Duplex 2 7 B RE XR3172E DE 3 6 A XR3175E XR3178E DI45 GND VCC A 1 8 8-Pin NSOIC Full Duplex RO 2 7 B XR3171E DI 3 6 Z XR3174E XR3177E GND Y 45 NC 1 14 VCC RO 2 13 NC 14-Pin NSOIC RE 3 12 A Full Duplex B DE 4 XR3170E 11 XR3173E DI 5 10 Z XR3176E GND 6 9 Y GND 78 NC ORDERING INFORMATION OPERATING TEMPERATURE PART NUMBER PACKAGE DEVICE STATUS RANGE XR3170EID 14-pin Narrow SOIC -40C to +85C Active XR3171EID 8-pin Narrow SOIC -40C to +85C Active XR3172EID 8-pin Narrow SOIC -40C to +85C Active XR3173EID 14-pin Narrow SOIC -40C to +85C Active XR3174EID 8-pin Narrow SOIC -40C to +85C Active XR3175EID 8-pin Narrow SOIC -40C to +85C Active XR3176EID 14-pin Narrow SOIC -40C to +85C Active XR3177EID 8-pin Narrow SOIC -40C to +85C Active XR3178EID 8-pin Narrow SOIC -40C to +85C Active Note: Please visit www.exar.com for tape and reel option part numbers. 2