The ADM4850-ADM4857 are differential line transceivers suitable for high speed full and half duplex data communication on multipoint bus transmission lines. They are designed for balanced data transmission and comply with EIA Standards RS-485 and RS-422. The ADM4850-ADM4853 are half duplex transceivers which share differential lines and have separate enable inputs for the driver and receiver. The full duplex ADM4854-ADM4857 transceivers have dedicated differential line driver outputs and receiver inputs.
The devices have a 1/8-unit-load receiver input impedance which allows up to 256 transceivers on a bus. Since only one driver should be enabled at any time, the output of a disabled or powered down driver is three-stated to avoid overloading the bus.
The receiver inputs have a true failsafe feature which ensures a logic high output level when the inputs are open or shorted. This guarantees that the receiver outputs are in a known state before communication begins and when communication ceases.
The driver outputs are slew rate limited in order to reduce EMI and data errors caused by reflections from improperly terminated buses. Excessive power dissipation caused by bus contention or by output shorting is prevented with a thermal shutdown circuit.
The parts are fully specified over the commercial and industrial temperature ranges and are available in 8-lead SOIC and LFCSP packages.
|Title||Content Type||File Type|
|ADM4850-ADM4857: 5 V, Slew-Rate Limited, Half-Duplex and Full-Duplex RS-485/RS-422 Transceivers Data Sheet (Rev D, 01/2012) (pdf, 453 kB)||Data Sheets|
|AN-1176: Component Footprints and Symbols in the Binary .Bxl File Format (pdf, 671 kB)||Application Notes|
|AN-960: RS-485/RS-422 Circuit Implementation Guide (pdf, 245 kB)||Application Notes|
Solving Isolation Challenges in Industrial Automation
This webcast will discuss the role isolation plays in providing protection and reducing the system bit-error-rate, using the specific design challenges of an RS-485 network. Topics to be covered in this presentation will include: Why and when one should isolate, Types of isolation and their advantages, Design Considerations for an RS-485 node (and how this translates to design considerations for signal isolation) as well as many other topics.
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Evaluation board for evaluating the RS485
The ezLINX™ iCoupler® Isolated Interface Development Environment provides developers with a cost-effective, plug and play method for evaluation eight physical layer, digitally-isolated communication standards.
Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.
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