TPS51200: REFOUT ripple issue

Tommy,

Based on this image, I have a couple of questions:

1. Do you also observe this noise on REFOUT, or also on VOUT? If this is not present on VOUT, it is possible that there is noise coupling from somewhere else on the board into your measured signal.
   1. Do you have any noisy signals on the PCB routed near this signal?
2. Are you saying that this signal is measured without R3169, or that this ripple is no longer present with this resistor removed?

Thanks,

Kadeem

Hi Kadeem,

Remove the R3169 measured result for REFOUT ripple noise.

Tommy,

Is the GND connection for the REFOUT probe connected? Does this noise also appear on VOUT? As is shown below, REFOUT is a buffered version of REFIN, so if there is no noise on REFIN, then there should not be noise on REFOUT.

A measurement of VOUT will help to determine if this noise is actually present, as VOUT tracks REFOUT.

Thanks,

Kadeem

Tommy,

We have not heard from you in a while - are you still observing this issue?

If so, do you have a measurement of REFIN/REFOUT.VOUT?

Thanks,

Kadeem