GTS Transceiver PHY User Guide: Agilex™ 5 FPGAs and SoCs

ID 817660
Date 4/07/2025
Public
Document Table of Contents

3.7.5. Input Reference Clock Buffer Protection

The GTS transceiver’s input reference clock buffers have a protection mechanism that prevents aging and damage to the buffer if the reference clock is left unconnected or there is no clock toggling activity on it. The protection mechanism detects when there is no toggling clock on the input buffers, and automatically turns off the buffer. The detection mechanism measures for clock frequencies between 25MHz to 380MHz, and any frequency out of this range causes the buffer to be turned off.

If the input reference clock is brought back up and stable, and there is a need to use it again, the buffer needs to be turned back on. There are two ways to do this:

  1. Reconfiguring the device.
  2. Performing read and write operations to the reference clock buffer register to indicate that the clock is back up.