Features and Benefits

  • Flexible reference inputs
  • Input frequencies: 8 kHz to 750 MHz
  • Two reference inputs
  • Loss of reference indicators
  • Auto and manual holdover modes
  • Auto and manual switchover modes
  • Smooth A-to-B phase transition on outputs
  • Excellent stability in holdover mode
  • Programmable 16 + 1-bit input divider, R
  • Differential HSTL clock output
  • Output frequencies to 750 MHz
  • Low jitter clock doubler for frequencies >
    400 MHz
  • Please see Data Sheet for additional features.

Product Details

The AD9549 provides synchronization for many systems, including synchronous optical networks (SONET/SDH). The AD9549 generates an output clock, synchronized to one of two external input references. The external references may contain significant time jitter, also specified as phase noise. Using a digitally controlled loop and holdover circuitry, the AD9549 continues to generate a clean (low jitter), valid output clock during a loss of reference condition, even when both references have failed.

The AD9549 operates over an industrial temperature range of −40°C to +85°C.


  • Network synchronization
  • Reference clock jitter cleanup
  • SONET/SDH clocks up to OC-192, including FEC
  • Stratum 3/3E reference clocks
  • Wireless base stations, controllers
  • Cable infrastructure
  • Data communications

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

Documentation & Resources

  • View All (20)
  • Data Sheets (1)
  • Application Notes (9)
  • Frequently Asked Questions (1)
  • Product Selection Guide (1)
  • Technical Articles (6)
  • Webcasts (2)
  • Application Notes
    Frequently Asked Questions

    Tools & Simulations

    IBIS Models

    AD9549 IBIS Models

    Evaluation Boards

    Pricing displayed is based on 1-piece.

    Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.

    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.