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AR# 41947

Multi-Gigibit Transceiver Hot-Plug Considerations


Virtex devices are used in some hot-plug designs.Special care must be taken to ensure the reliability of the design.Industry accepted best practices need to be employed to protect the device from damage. This Answer Record lists a few of the most important considerations. This list is not exhaustive.


1. Electro Static Discharge(ESD) diodes protect the MGT from damage, and they are based on power and ground being present. Ground and voltage pins are usually staged onthe hot-swap boardconnectors with ground pins connecting before voltage pins,and voltage pins connecting before the general I/O pins.This includes FPGA pins that are in the hot-insertion path. For more details, see the Hot-Swapping Virtex-II, Virtex-II Pro, Virtex-4, and Virtex-5 Devices Application Note(XAPP251): http://www.xilinx.com/support/documentation/application_notes/xapp251.pdf

2.To avoid over driving the ESD diodes while the power is ramping up, transmitting to an MGT device while it is being plugged in should be avoided.Most protocols have provisions for determining if a channel is present. These can be used to turn the transmitter down oroff. Detailed ESD protection specifications can be found in the Device Reliability Report (UG116):http://www.xilinx.com/support/documentation/user_guides/ug116.pdf

3. AC couplingwith an external capacitoronGT signal lines is strongly recommendedforhot-plug designs to block any DC currents that might occur.

4. Follow proper ESD precautionswhen handling boards that are not plugged in. ESD damage to a device can be subtle and can degrade device performance without causing a total failure.

AR# 41947
Date Created 05/06/2011
Last Updated 12/15/2012
Status Active
Type General Article
  • Virtex