Tool/software: WEBENCH® Design Tools
Hello David Baba,
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The Switch node waveform looks fine to me. It also looks stable. The likely reason why your part is failing is due to an overshoot at the input when starting up or making a fast transition of the input voltage. As I mentioned previously, should place a 2.2uF ceramic very close to the input to the device (Vin and Gnd) and also place sufficient damping at the input supply to your board where the power connects, to avoid overshoot of the input voltage due to parasitic inductances/ringing. I recommend trying a 33uF electrolytic with an ESR of ~0.5ohm as a damping cap. I hope this helps with your issue?
Kind regards,
David Baba.
Hello David ,
Hello Ravi,
It does look as though the the inductor is saturating, also I do not recommend using an open core inducor with a COT control architecture because COT uses a feedback comparator, in contrast to an Error Amplifier with a relatively low BW as in the case of the LM part you mentioned. I recommend using a shield inductor with COTs I suggest replacing with a shielded inductor with specs we know are suitable to determine for sure, its the inductor.
Kind regards,
David.