3.3 V Slew Rate Limited, Half Duplex RS-485/RS-422 Transceiver ADM3493 FEATURES FUNCTIONAL BLOCK DIAGRAM V Operates with 3.3 V supply CC Interoperable with 5 V logic ADM3493 EIA RS-422 and RS-485 compliant over full CM range R RO Data rate: 250 kbps A Half duplex transceiver RE Reduced slew rates for low EMI DE B 2 nA supply current in shutdown mode DI D Up to 256 transceivers on a bus 7 V to +12 V bus common-mode range GND Specified over 40C to +85C temperature range Figure 1. 8 ns skew Available in 8-lead SOIC APPLICATIONS Low power RS-485 applications EMI sensitive systems DTE-DCE interfaces Industrial control Packet switching Local area networks Level translators GENERAL DESCRIPTION The receiver input impedance is 96 k, allowing up to 256 transceivers to be connected on the bus. A thermal shutdown The ADM3493 is a low power, differential line transceiver circuit prevents excessive power dissipation caused by bus designed to operate using a single 3.3 V power supply. Low contention or by output shorting. If a significant temperature power consumption, coupled with a shutdown mode, makes it increase is detected in the internal driver circuitry during fault ideal for power-sensitive applications. The ADM3493 is suitable conditions then the thermal shutdown circuit forces the driver for communication on multipoint bus transmission lines. output into a high impedance state. The receiver contains a fail- safe feature that results in a logic high output state, if the inputs The device contains one driver and one receiver. Designed for are unconnected (floating). half-duplex communication, the ADM3493 features a slew rate limited driver that minimizes EMI and reduces reflections The ADM3493 is fully specified over the commercial and caused by improperly terminated cables, allowing error-free industrial temperature ranges and is available in an 8-lead SOIC. data transmission at data rates up to 250 kbps. Rev. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 05715-001ADM3493 TABLE OF CONTENTS Features .............................................................................................. 1 Switching Characteristics .................................................................8 Applications....................................................................................... 1 Typical Performance Characteristics ..............................................9 Functional Block Diagram .............................................................. 1 Circuit Description......................................................................... 11 General Description ......................................................................... 1 Reduced EMI and Reflections .................................................. 11 Revision History ............................................................................... 2 Low Power Shutdown Mode..................................................... 11 Specifications..................................................................................... 3 Driver Output Protection.......................................................... 11 Timing Specifications .................................................................. 4 Propagation Delay...................................................................... 11 Absolute Maximum Ratings............................................................ 5 Typical Applications................................................................... 11 ESD Caution.................................................................................. 5 Outline Dimensions....................................................................... 12 Pin Configurations and Function Descriptions ........................... 6 Ordering Guide .......................................................................... 12 Test Circuits....................................................................................... 7 REVISION HISTORY 10/05Rev. 0: Initial Version Rev. 0 Page 2 of 12