ADM487EARZ Analog Devices

5 V, 15 kV ESD Protected Half-Duplex, RS-485/RS-422 Transceivers ADM485E/ADM487E/ADM1487E FEATURES FUNCTIONAL BLOCK DIAGRAM V CC TIA/EIA RS-485/RS-422 compliant ESD protection on RS-485 I/O pins ADM485E/ ADM487E/ 15 kV human body model (HBM) ADM1487E Data rates RO ADM487E: 250 kbps R ADM485E/ADM1487E: 2.5 Mbps RE A Half-duplex Reduced slew rates for low EMI DE B Common-mode input range: 7 V to +12 V DI D Thermal shutdown and short-circuit protection 8-lead SOIC packages ADM487EW qualified for automotive applications GND Figure 1. APPLICATIONS Energy/power metering Lighting systems Industrial control Telecommunications Security systems Instrumentation GENERAL DESCRIPTION The ADM485E/ADM487E/ADM1487E are 5 V, low power The driver outputs are slew rate limited to reduce EMI and data data transceivers with 15 kV ESD protection suitable for half- errors caused by reflections from improperly terminated buses. duplex communication on multipoint bus transmission lines. Excessive power dissipation caused by bus contention or output shorting is prevented with a thermal shutdown circuit. They are designed for balanced data transmission and comply with Telecommunication Industry Association/Electronics The parts are fully specified over the industrial temperature Industries Association (TIA/EIA) standards RS-485 and RS-422. ranges and are available in 8-lead SOIC packages. The ADM487E and ADM1487E have a 1/4 unit load receiver input impedance that allows up to 128 transceivers on a bus, whereas the ADM485E allows up to 32 transceivers on a bus. Because only one driver is enabled at any time, the output of a disabled or power-down driver is three-stated to avoid overloading the bus. Table 1. Selection Table Guaranteed Part Half-/Full- Data Rate Slew Rate Low Power Driver/Receiver Quiescent Number of Pin Number Duplex (Mbps) Limited Shutdown Enable Current (A) Nodes on Bus Count ADM485E Half 2.5 No No Yes 300 32 8 ADM487E Half 0.25 Yes Yes Yes 120 128 8 ADM1487E Half 2.5 No No Yes 230 128 8 Rev. B 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 20072010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 06356-001ADM485E/ADM487E/ADM1487E TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................8 Applications....................................................................................... 1 Test Circuits and Switching Characteristics................................ 11 Functional Block Diagram .............................................................. 1 Theory of Operation ...................................................................... 13 General Description ......................................................................... 1 Circuit Description .................................................................... 13 Revision History ............................................................................... 2 Applications Information .............................................................. 15 Specifications..................................................................................... 3 Differential Data Transmission ................................................ 15 Timing Specifications .................................................................. 4 Cable and Data Rate................................................................... 15 Absolute Maximum Ratings............................................................ 6 Outline Dimensions....................................................................... 16 ESD Caution.................................................................................. 6 Ordering Guide .......................................................................... 16 Pin Configuration and Function Descriptions............................. 7 Automotive Products................................................................. 16 REVISION HISTORY 10/10Rev. A to Rev. B Added ADM487EW Qualified for Automotive Applications to Features Section ................................................................................ 1 Updated Outline Dimensions ....................................................... 16 Changes to Ordering Guide .......................................................... 16 Added Automotive Products Section .......................................... 16 3/08Rev. 0 to Rev. A Changes to Supply Voltage Range ....................................Universal Added Endnote 1.............................................................................. 3 Changes to Table 3............................................................................ 4 Changes to Table 4............................................................................ 5 Changes to Figure 12........................................................................ 9 Changes to Figure 27 and Table 9................................................. 14 Changes to Figure 29...................................................................... 15 Updated Outline Dimensions ....................................................... 16 1/07Revision 0: Initial Version Rev. B Page 2 of 16