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AR# 68928

XAPP589, XAPP1241, XAPP1276, XAPP591, XAPP1308 - (PICXO/FRACXO) What are the differences between these Application Notes? Which one should I use?


Xilinx provides XAPP589, XAPP1241, XAPP1276, XAPP591, and XAPP1308 for replacing VCXO solutions.

What are the differences between them and which one should I select in my application?


  • XAPP589 (PICXO) is a VCXO replacement for 7 Series/ Zynq 7000. It uses the Phase Interpolator to replace a VCXO. It can lock the transmitting GT to a signal frequency close to the main PLL output rate providing a per channel locked data rate output.

  • XAPP1241 (PICXO) is a VCXO replacement for UltraScale architectures. It uses the same method as XAPP589.

  • XAPP1276 (FRACXO) is a VCXO replacement using a Fractional PLL for UltraScale architectures. It achieves the same as XAPP589/XAPP1241 but uses the fractional PLL directly to generate locked rates.
    It provides more tuning range than the two XAPPs above with a lower jitter output and is available on GTs with a Fractional QPLL capability.

  • XAPP591 is a Video SDI pass through design. It gives an example of PICXO (XAPP589) into an SDI system. It can be used as a basis for building more complex SDI designs.

  • XAPP1308 is a Video Hsync locking solution. It uses two PICXO stages to lock the TX GT onto an incoming video HSync signal.
AR# 68928
Date 05/09/2017
Status Active
Type General Article
  • Artix-7
  • SoC
  • Kintex UltraScale
  • More
  • Kintex UltraScale+
  • Kintex-7
  • Kintex-7Q
  • Virtex UltraScale
  • Virtex UltraScale+
  • Virtex-7
  • Virtex-7Q
  • Less
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