1. Products
  2. Interface and Isolation
  3. RS-232 / RS-422 / RS-485 / RS-562
  4. RS-485 and RS-422
  5. ADM3491-1


Features and Benefits

  • Operates with 3.3 V supply
  • EIA RS-422 and RS-485 compliant over full CM range
  • 19 kΩ input impedance
  • Up to 50 transceivers on bus
  • 20 Mbps data rate
  • Short-circuit protection
  • Specified over full temperature range
  • Thermal shutdown
  • Interoperable with 5 V logic
  • 840 μA supply current
  • 2 nA shutdown current
  • See data sheet for additional features

Product Details

The ADM3491-1 is a low power, differential line transceiver designed to operate using a single 3.3 V power supply. Low power consumption, coupled with a shutdown mode, makes it ideal for power-sensitive applications. It is suitable for communication on multipoint bus transmission lines.

The ADM3491-1 is intended for balanced data transmission and complies with both Electronic Industries Association (EIA) Standards RS-485 and RS-422. It contains a differential line driver and a differential line receiver, making it suitable for full-duplex data transfer.

The input impedance is 19 kΩ, allowing up to 50 transceivers to be connected on the bus. A thermal shutdown circuit prevents excessive power dissipation caused by bus contention or by output shorting. This feature forces the driver output into a high impedance state if a significant temperature increase is detected in the internal driver circuitry during fault conditions.

If the inputs are unconnected (floating), the receiver contains a fail-safe feature that results in a logic high output state.

The ADM3491-1 is fabricated on BiCMOS, an advanced mixed technology process combining low power CMOS with fast switching bipolar technology.


  • Telecommunications
  • DTE–DCE interface
  • Packet switching
  • Local area networks
  • Data concentration
  • Data multiplexers
  • Integrated services digital network (ISDN)
  • AppleTalk Industrial controls

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
ADM3491ANZ-1 Material Declaration Reliability Data 14-Lead PDIP
ADM3491ARU-1 Material Declaration Reliability Data 16-Lead TSSOP
ADM3491ARU-1REEL Material Declaration Reliability Data 16-Lead TSSOP
ADM3491ARUZ-1 Material Declaration Reliability Data 16-Lead TSSOP
ADM3491ARUZ-1REEL Material Declaration Reliability Data 16-Lead TSSOP
ADM3491ARUZ-1REEL7 Material Declaration Reliability Data 16-Lead TSSOP
ADM3491ARZ-1 Material Declaration Reliability Data 14-Lead SOIC
ADM3491ARZ-1REEL Material Declaration Reliability Data 14-Lead SOIC
ADM3491ARZ-1REEL7 Material Declaration Reliability Data 14-Lead SOIC
Wafer Fabrication Data

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Sample & Buy

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