The ADM2485 differential bus transceiver is an integrated, galvanically isolated component designed for bidirectional data communication on multipoint bus transmission lines. It is designed for balanced transmission lines and complies with ANSI/TIA/EIA RS-485-A-98 and ISO 8482:1987(E).
The device employs Analog Devices, Inc., iCoupler ® technology to combine a 3-channel isolator, a three-state differential line driver, and a differential input receiver into a single package. An on-chip oscillator outputs a pair of square waveforms that drive an external transformer to provide isolated power with an external transformer. The logic side of the device can be powered with either a 5 V or a 3.3 V supply, and the bus side is powered with an isolated 5 V supply.
The ADM2485 driver has an active high enable. The driver differential outputs and the receiver differential inputs are connected internally to form a differential input/output port that imposes minimal loading on the bus when the driver is disabled or when VDD1 or VDD2 = 0 V. Also provided is an active high receiver disable that causes the receive output to enter a high impedance state.
The device has current-limiting and thermal shutdown features to protect against output short circuits and situations where bus contention might cause excessive power dissipation. The part is fully specified over the industrial temperature range and is available in a 16-lead, wide-body SOIC package.
Data Sheet, Rev. A, 12/07
|Title||Content Type||File Type|
|ADM2485: High Speed, Isolated RS-485 Transceiver with Integrated Transformer Driver Data Sheet (Rev A, 12/2007) (pdf, 580 kB)||Data Sheets|
|AN-960: RS-485/RS-422 Circuit Implementation Guide (pdf, 245 kB)||Application Notes|
|AN-0971: Recommendations for Control of Radiated Emissions with isoPower Devices (pdf, 406 kB)||Application Notes|
|AN-913: Isolating I2C Interfaces (pdf, 280 kB)||Application Notes|
|AN-793: ESD/Latch-Up Considerations with iCoupler® Isolation Products (pdf, 246 kB)||Application Notes|
|AN-825: Power Supply Considerations in iCoupler Isolation Products (pdf, 181 kB)||Application Notes|
|CN-0031: Half-Duplex, Isolated RS-485 Interface (pdf, 88 kB)||Circuit Note|
Solving Isolation Challenges in Power Conversion Applications
This webcast will present solutions to isolation challenges in power conversion applications. Among the topics to be discussed are the limitations of traditional methods of isolation (such as utilization of optocouplers and pulse transformers) vs. more efficient and cost effective solutions that utilize digital isolators. If you are currently using optocouplers and pulse transformers, this is a webcast you should attend.
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.
|UG-213: Evaluation Board for the ADM2485 Half-Duplex, Isolated RS-485 Transceiver with Transformer Driver (pdf, 293 kB)||User Guides|
High-Performance Multichannel Power-Line Monitoring with Simultaneous-Sampling ADCs
By Colm Slattery, Analog Devices, Inc. (Analog Dialogue, Vol. 41, January 2007)
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|Test & Instrumentation Solutions Bulletin, Volume 10, Issue 3 (pdf, 1334 kB)||Solutions Bulletins|
|How do I learn about new iCoupler products?||FAQs/RAQs||HTML|
|Are iCoupler products Pb-free?||FAQs/RAQs||HTML|
|Can I replace an optocoupler with an iCoupler product in an existing design?||FAQs/RAQs||HTML|
|What are some of the distinguishing features of the iCoupler products?||FAQs/RAQs||HTML|
|What communications protocols are supported by iCoupler products?||FAQs/RAQs||HTML|
|What are the different types of iCoupler products?||FAQs/RAQs||HTML|
|Do iCoupler products have VDE certification for reinforced insulation?||FAQs/RAQs||HTML|
|With which regulatory standards do iCoupler products comply?||FAQs/RAQs||HTML|
|How much isolation can iCoupler products provide?||FAQs/RAQs||HTML|
|What are the benefits of iCoupler technology?||FAQs/RAQs||HTML|
|What is iCoupler technology?||FAQs/RAQs||HTML|
|What types of technologies have been used to provide isolation?||FAQs/RAQs||HTML|
|What are optocouplers? What is optical isolation?||FAQs/RAQs||HTML|
|What is capacitive isolation?||FAQs/RAQs||HTML|
|What regulatory standards address isolation products?||FAQs/RAQs||HTML|
|What is isolation? Why is it needed?||FAQs/RAQs||HTML|
|What are common applications that use isolation?||FAQs/RAQs||HTML|
|How is isolation specified?||FAQs/RAQs||HTML|
|What is isolation rating?||FAQs/RAQs||HTML|
|What is the relationship between working voltage and isolation rating?||FAQs/RAQs||HTML|
|What is the difference between basic and double (or reinforced) insulation levels?||FAQs/RAQs||HTML|
|What are transient immunity and common-mode rejection?||FAQs/RAQs||HTML|
|What other parameters are important when considering an isolation device?||FAQs/RAQs||HTML|
|RAQs index||Rarely Asked Questions||HTML|
|Glossary of EE Terms||Glossary||HTML|
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.
Evaluation board for evaluating the ADM2485 2.5 kV Signal Isolated, High Speed (16 Mbps), Half Duplex RS-485 Transceiver w/ Transformer Driver
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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