Dual PLL, Asynchronous Clock Generator

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Part Details
Part Models 2
1ku List Price Starting From $4.25
  • Single, low phase noise, fully integrated VCO/fractional-N PLL core
    • VCO range: 2375 MHz to 2725 MHz 
    • Integrated loop filter (requires a single external capacitor)
    • 2 differential, XTAL, or single-ended reference inputs
    • Reference monitoring capability
    • Automatic redundant XTAL switchover
    • Minimal transient, smooth switching
    • Typical RMS jitter
      • <0.3 ps (12 kHz to 20 MHz), integer-N translations
      • <0.5 ps (12 kHz to 20 MHz), fractional-N translations
    • Input frequency
      • 8 kHz, 1.544 MHz, 2.048 MHz, and 10 MHz to 325 MHz
    • Preset frequency translations via pin strapping (PPRx)
      • Using a 25 MHz input reference
        • 24.576 MHz, 25 MHz, 33.33 MHz, 50 MHz, 70.656 MHz, 100 MHz, 125 MHz, 148.5 MHz, 156.25 MHz, 161.1328 MHz, 312.5 MHz, 322.2656 MHz, 625 MHz, or 644.5313 MHz
      • Using a 19.44 MHz input reference
        • 50 MHz, 100 MHz, 125 MHz, 156.25 MHz, 161.1328 MHz, or 644.5313 MHz
      • Using a 30.72 MHz input reference
        • 25 MHz, 50 MHz, 100 MHz, 125 MHz, or 156.25 MHz
  • Single, general-purpose, fully integrated VCO/integer-N PLL core
    • VCO range: 750 MHz to 825 MHz
    • Integrated loop filter
    • Independent, duplicate reference input or operation from the fractional-N PLL active reference input
    • Input frequency: 25 MHz
    • Preset frequency translations via pin strapping (PPRx)
      • 25 MHz, 33.33 MHz, 50 MHz, 66.67 MHz, 100 MHz, 133.33 MHz, 200 MHz, or 400 MHz
    • Up to 3 copies of reference clock output
  • 11 pairs of configurable differential outputs
    • Output drive formats
      • 3 outputs: HSTL, LVDS, HCSL, 1.8 V CMOS, 2.5 V/3.3 V CMOS
      • 8 outputs: HSTL, LVDS, or 1.8 V CMOS
  • 2.5 V or 3.3 V single-supply operation
Additional Details
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The AD9576 provides a multiple output clock generator function comprising two dedicated phase-locked loop (PLL) cores with flexible frequency translation capability, optimized to serve as a robust source of asynchronous clocks for an entire system, providing extended operating life within frequency tolerance through monitoring of and automatic switchover between redundant crystal (XTAL) inputs with minimized switching, induced transients. The fractional-N PLL design is based on the Analog Devices, Inc., proven portfolio of high performance, low jitter frequency synthesizers to maximize network performance, whereas the integer-N PLL provides general-purpose clocks for use as CPU and field-programmable gate array (FPGA) reference clocks.

The AD9576 uses pin strapping to select among a multitude of power-on ready configurations for its 11 output clocks, which require only the connection of external pull-up or pull-down resistors to the appropriate pin program reader pins (PPRx). These pins provide control of the internal dividers for establishing the desired frequency translations, clock output functionality, and input reference functionality. These parameters can also be manually configured through a serial port interface (SPI).

The AD9576 is packaged in a 64-lead, 9 mm × 9 mm LFCSP, requiring only a single 2.5 V or 3.3 V supply. The operating temperature range is −40°C to +85°C.

Each OUTx output is differential and contains two pins: OUTx and OUTx. For simplicity, the term OUTx refers to the functional output block containing these two pins..


  • Ethernet line cards, switches, and routers
  • Baseband units
  • SATA and PCI express
  • Low jitter, low phase noise clock generation
  • Asynchronous clock generation
Part Models 2
1ku List Price Starting From $4.25

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Software and Part Ecosystem

Software and Part Ecosystem

Evaluation Kit

Evaluation Kits 1

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AD9576 Evaluation Board



AD9576 Evaluation Board

AD9576 Evaluation Board

Features and Benefits

  • Simple power connection using 6V wall adapter and on-board LDO voltage regulators
  • 8 ac-coupled single-ended (differential signal recombined via a bal-un) output SMA connectors terminated for HSTL or LVDS
  • 3 ac-coupled differential output SMA connectors terminated for CMOS
  • 3 configurable reference inputs, selectable between a single ended to differential reference input SMA connector, a 25 MHz on-board XTAL, or a 25 MHz on-board XO.
  • Pin programmable, power on ready configurability
  • Status LEDs
  • USB connection to PC
  • Microsoft Windows-based evaluation software with simple graphical user interface via an ACE plug-in module

Product Detail

The AD9576 evaluation board is a compact, easy-to-use platform for evaluating all features of the AD9576 dual channel, power-on ready clock generator.

Tools & Simulations

Tools & Simulations 2

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

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