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AD9547网络时钟与同步方案

• AD9547是双路/四路输入网络时钟发生器/同步器,能为许多系统包括同步光网络(SONET/SDH)提供同步.输入基准频率从1 kHz 到750 MHz,频率监视1ppm,输出频率高达450MHz,主要应用在网络同步,OC-192的SONET/SDH时钟,无线基站,控制器,有线基础设备和数据通信. 本文介绍了AD9547主要特性, 功能方框图,详细方框图, 输出同步方框图和评估板电路图以及评估板材料清单.
  
  AD9547: Dual/Quad Input Network Clock Gene一体电感器rator/Synchronizer
  
  The AD9547 provides synchronization for many systems, including synchronous optical networks (SONET/SDH). The AD9547 generates an output clock that is synchronized to one of two di绕行电感fferential or four single-ended external input references. The digital PLL allows for reduction of input time jitter or phase noise associated with the external references. The AD9547 continuously generates a clean (low jitter), valid output clock, even when all references fail, by means of digitally controlled loop and hol广州电感器dover circuitry. The AD9547 operates over an industrial temperature range of −40℃ to +85℃.
  
  AD9547主要特性:
  
  Supports Stratum 2 stability in holdover mode
  
  Supports reference swi电感生产厂家tchover with phase build-out
  
  Supports hitless reference switchover
  
  Automatic/manual holdover and reference switchover
  
  2 pairs of reference input pins, with each pair configurable as a single differential input or as 2 independent single-ended inputs
  
  Input reference frequencies from 1 kHz to 750 MHz
  
  Reference validation and frequency monitoring (1 ppm)
  
  Programmable input reference switchover priority
  
  30-bit programmab大电流电感le input reference divider
  
  2 pairs of clock output pins, with each pair configurable as a single differential LVDS/LVPECL output or as 2 single-ended CMOS outputs
  
  Output frequencies up to 450 MHz
  
  20-bit integer and 10-bit fractional programmable feedback divider
  
  Programmable digital loop filter covering loop bandwidths from 0.001 Hz to 100 kHz
  
  Optional low noise LC-VCO system clock multiplier
  
  Optional crystal resonator for system clock input
  
  On-chip EEPROM to store multiple power-up profiles
  
  Software controlled power-down
  
  64-lead LFCSP package
  
  AD9547应用:
  
  Network synchronization
  
  Cleanup of reference clock jitter
  
  SONET/SDH clocks up to OC-192, including FEC
  
  Stratum 2 holdover, jitter cleanup, and phase transient control
  
  Stratum 3E and Stratum 3 reference clocks
  
  Wireless base stations, controllers
  
  Cable infrastructure
  
  Data communications
  
  图1.AD9547功能方框图
  

  图2.AD9547详细方框图

  
  
  图3.AD9547输出同步方框图
  
  图4.AD9547评估板电路图(1)
  
  
  图5.AD9547评估板电路图(2)
  
  
  图6.AD9547评估板电路图(3)
  
  

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