Dear team,
We test soft start waveform on our board. Based on datasheet description, device SS pin use 2uA charging Css.
But we find there is two step at SS pin. Could you let us know why there are two step at SS waveform?
Regards,
Ben
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Dear team,
We test soft start waveform on our board. Based on datasheet description, device SS pin use 2uA charging Css.
But we find there is two step at SS pin. Could you let us know why there are two step at SS waveform?
Regards,
Ben
Hi Ben,
I will need to check on an EVM or with design for any reference on this. Are you testing this on an EVM or a custom board? Can you possibly share the schematic and other details on conditions under which this is being tested like Vin and Iout (eload or resistive load)? VOUT looks to be around 2.7V?
Thanks,
Amod
Hi Amod,
I applied one EVM but not get it yet. Could you help to confirm from your side?
Another question is, what is maximum voltage level at SS pin?
Output voltage is 2.5V, the waveform shows 2.7V should be issue from resolution of scope setting.
Partial schematic as below, there are no issue at output side(Lout/Cout). It's follow datasheet recommendation and we have qualified this design before.
Regards,
Ben
Hi Ben,
SS is most likely pulled up to VREG5 (~5.5V) and should not exceed that value. I am confirming with designer too. I do not have an EVM either to confirm so trying to double check with design on this. Will update you once I receive an answer.
Thanks,
Amod
I confirmed with design and the SS is pulled to VREG5 level after the soft-start is finished. So, the waveform you observe is expected.
This feedback is from design team