SPRUIM6A October 2018 – November 2020
ISSUE: A resonance was observed between the filter and the SoC for the following power pins due to a lack of bulk capacitance after the filter.
This has led to some noise on the internal power supply rails, resulting an increase in jitter on the Ethernet subsystem source clocks.
SOLUTION: A 4.7-uF capacitor was added from the SoC side of the above filters to ground to add sufficient bulk capacitance to dampen the resonance. Customers should include a footprint for a 4.7-uF capacitor in their designs to avoid this issue.
WORKAROUND: 4.7-uF capacitors can be added to the specified rails if problems are observed. Contact Texas Instruments for specific instructions if the change is needed.