TPS40428: How to reduce ripple

Hello Srinavas,

DC/DC output voltage ripple can be very sensitive to the measurement methodology and actually has very little to do with the choice of controller like TPS40428. Usually measurements with a lot of high frequency noise can be due to the location on the PCB of probing, or noise pick-up from the probe itself (like an antenna to switching nets on the board like SW). I suggest to have a look at these links and first try to see if cleaning up the probing technique helps.

There are several methods discussed, but usually the best for a high current converter is to measure directly across a good high frequency capacitor with a differential probe.

https://training.ti.com/power-tips-measuring-vout-ripple-dcdc-converters

https://e2e.ti.com/blogs_/b/powerhouse/posts/how-you-measure-your-ripple-can-make-you-or-break-you