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SIMPLE SWITCHER® - Forum
Ringing on Vin of LM2674 and RC snubber
I have inherent ringing on the input and output of the LM2674 switching regulator. The design flaw is in the traces being used to connect the regulator. However since our customer doesn't want us to respin the boards, we're being forced to look at other solutions.
I came across using a RC snubber circuit, however the documentation from ti shows this cleans up the ringing on the output. Does the same effect also happen on the input via the feed back loop?
The snubber is designed to reduce SW node ringing. This ringing will appear at both the input and output nodes and therefore the snubber will reduce both.
However, excessive ringing due to poor pcb layout will not necessarily be solved with a snubber. Adding more ceramic input capacitance, mounted close between the VIN pin and diode ground may be more effective. Because this problem involves pcb trace parasitics, I suggest that you experiment with input caps as well as a snubber to get the best result.
We are looking to implement a ceramic cap to help with the high frequency noise. We'll experiment with a snubber to help.
Thanks again for the help!
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