Part Number:TPS54202
We are using TPS54202DDCR to provide 5V from the input voltage with a range of 21-25V. The output current varies between 2mA when in sleep and 40mA and 600mA in normal operation. For most part it works fine, but there is a small instability that causes audio noise, which we really need to get rid of. We have followed the design guide and also used your simulation tool to see if we can optimize this, but have not had much luck. The layout is identical to your recommendation, so we are sure that is not the issue. We changed the output inductor with various values from 10uH to 47uH, with the output cap of 3x 22uF ceramic, as recommended. The feed forward capacitor is 82pF, but have gone up to 150pF and down to 50pF with no improvement. The instability we see is not all that big and it causes output ripple of roughly ~40mV, but due to its frequency components it is causing us a lot of issue with noise that we cannot filter. Would really appreciate some insight and design guidance to get passed this. Thanks. Rick