5 V, Slew-Rate Limited, Half-Duplex and Full-Duplex RS-485/RS-422 Transceivers ADM4850/ADM4851/ADM4852/ADM4853/ADM4854/ADM4855/ADM4856/ADM4857 FEATURES FUNCTIONAL BLOCK DIAGRAMS V CC EIA RS-485-/RS-422-compliant Data rate options ADM4850/ADM4851/ ADM4852/ADM4853 ADM4850/ADM4854: 115 kbps ADM4851/ADM4855: 500 kbps RO R ADM4852/ADM4856: 2.5 Mbps A RE ADM4853/ADM4857: 10 Mbps Half- and full-duplex options B DE Reduced slew rates for low EMI DI D True fail-safe receiver inputs 5 A (maximum) supply current in shutdown mode Up to 256 transceivers on one bus GND Outputs high-Z when disabled or powered off Figure 1. 7 V to +12 V bus common-mode range V CC Thermal shutdown and short-circuit protection ADM4854/ADM4855/ Pin-compatible with the MAX308x ADM4856/ADM4857 Specified over the 40C to +85C temperature range Available in 8-lead SOIC, LFCSP, and MSOP packages A RO R Qualified for automotive applications B APPLICATIONS Z Low power RS-485 applications DI D Y EMI-sensitive systems DTE-DCE interfaces Industrial control GND Packet switching Figure 2. Local area networks Level translators before communication begins and when communication ends. GENERAL DESCRIPTION The driver outputs are slew-rate limited to reduce EMI and data The ADM4850/ADM4851/ADM4852/ADM4853/ADM4854/ errors caused by reflections from improperly terminated buses. ADM4855/ADM4856/ADM4857 are differential line transceivers Excessive power dissipation caused by bus contention or by output suitable for high speed half- and full-duplex data communication on shorting is prevented with a thermal shutdown circuit. multipoint bus transmission lines. They are designed for balanced The parts are fully specified over the commercial and industrial data transmission and comply with EIA Standards RS-485 and temperature ranges and are available in 8-lead SOIC, LFCSP RS-422. The ADM4850/ADM4851/ADM4852/ADM4853 are half- (ADM4850/ADM4851/ADM4852/ADM4853), and MSOP duplex transceivers that share differential lines and have separate (ADM4850 only) packages. enable inputs for the driver and receiver. The full-duplex ADM4854/ADM4855/ADM4856/ADM4857 transceivers have Table 1. Selection Table dedicated differential line driver outputs and receiver inputs. Part No. Half-/Full-Duplex Data Rate The parts have a 1/8-unit-load receiver input impedance, which ADM4850 Half 115 kbps ADM4851 Half 500 kbps allows up to 256 transceivers on one bus. Because only one driver ADM4852 Half 2.5 Mbps should be enabled at any time, the output of a disabled or pow- ADM4853 Half 10 Mbps ered-down driver is three-stated to avoid overloading the bus. ADM4854 Full 115 kbps The receiver inputs have a true fail-safe feature, which ensures ADM4855 Full 500 kbps a logic high output level when the inputs are open or shorted. ADM4856 Full 2.5 Mbps This guarantees that the receiver outputs are in a known state ADM4857 Full 10 Mbps Rev. D 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 20042012 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 04931-028 04931-001ADM4850/ADM4851/ADM4852/ADM4853/ADM4854/ADM4855/ADM4856/ADM4857 TABLE OF CONTENTS Features .............................................................................................. 1 Test Circuits..................................................................................... 11 Applications....................................................................................... 1 Switching Characteristics .............................................................. 12 Functional Block Diagrams............................................................. 1 Circuit Description......................................................................... 13 General Description ......................................................................... 1 Slew-Rate Control ...................................................................... 13 Revision History ............................................................................... 2 Receiver Input Filtering............................................................. 13 Specifications..................................................................................... 3 Half-/Full-Duplex Operation ................................................... 13 ADM4850/ADM4854 Timing Specifications........................... 4 High Receiver Input Impedance .............................................. 14 ADM4851/ADM4855 Timing Specifications........................... 4 Three-State Bus Connection..................................................... 14 ADM4852/ADM4856 Timing Specifications........................... 5 Shutdown Mode ......................................................................... 14 ADM4853/ADM4857 Timing Specifications........................... 5 Fail-Safe Operation .................................................................... 14 Absolute Maximum Ratings............................................................ 6 Current Limit and Thermal Shutdown ................................... 14 ESD Caution.................................................................................. 6 Outline Dimensions....................................................................... 15 Pin Configurations and Function Descriptions ........................... 7 Ordering Guide .......................................................................... 16 Typical Performance Characteristics ............................................. 9 Automotive Product................................................................... 16 REVISION HISTORY 1/12Rev. C to Rev. D Change to Features Section ............................................................. 1 Changes to Ordering Guide .......................................................... 15 Added Automotive Products Section .......................................... 15 1/11Rev. B to Rev. C Change to Table 8, Pin 3 Description ............................................ 7 Changes to Figure 29...................................................................... 12 Changes to Ordering Guide .......................................................... 15 7/09Rev. A to Rev. B Added MSOP Package .................................................. Throughout Changes to Table 2............................................................................ 3 Changes to Table 7............................................................................ 6 Added Figure 4 Renumbered Figures Sequentially..................... 7 Moved Typical Performance Characteristics Section .................. 8 Changes to Figure 24, Figure 27 ................................................... 11 Changes to Figure 29...................................................................... 12 Change to Shutdown Mode Section............................................. 13 Updated Outline Dimensions ....................................................... 14 Changes to Ordering Guide .......................................................... 15 4/09Rev. 0 to Rev. A Changes to Ordering Guide .......................................................... 15 10/04Revision 0: Initial Version Rev. D Page 2 of 16