ADM2485

2.5 kV Signal Isolated, High Speed (16 Mbps), Half Duplex RS-485 Transceiver w/ Transformer Driver

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Product Details

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.

Applications

  • Isolated RS-485/RS-422 interfaces
  • PROFIBUS networks
  • Industrial field networks
  • Multipoint data transmission systems

Product Lifecycle

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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.

Evaluation Kits

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EVAL-ADM2485

Product Details

The ADM2485 evaluation board allows the ADM2485 isolated RS-485 transceiver to be quickly and easily evaluated. The evaluation board allows all of the input and output functions to be exercised without the need for external components. When the ADM2485 is powered by 3.3 V on the logic side, a transformer, TI, is required with a turns ratio of 1:2.2 (DA2304_AL) to step up the 3.3 V to 6 V. This ensures that there is enough headroom for the ADP667 LDO to output a regulated 5 V output (EVAL-ADM2485EB3Z).

If the ADM2485 is powered by 5 V on the logic side, a trans-former, TI, is required with a turns ratio of 1:1.5 (DA2303_AL) so that there is enough headroom for the ADP667 LDO to output a regulated 5 V output (EVAL-ADM2485EB5Z).

Reference Designs

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CN0031

CN0031 Circuit Diagram

Reference Materials

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Design Resources

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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.

ADM2485 Material Declaration
PCN-PDN Information Quality And Reliability Symbols and Footprints

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The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


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Evaluation Boards Pricing displayed is based on 1-piece.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.