LMR14030-Q1 WSON Soft-start

Hi,

We have received your question and i will forward this to the product application engineer for the product

Thanks
-Arief

Hi,

How is the EN pin connected? If the pin is connected to VIN pin directly, then there is no such limitation of Css value. If the EN pin is connected to external controled signal, then it's better to leave Css no more larger than 4.7nF.

BR

Luke

Hi, Luke.

EN pin is connected to external circuit, not to VIN.

I have more question

1.Why do Css have a maximum value restrictions? When doing more than recommended value, what happens?

2..Why do only WSON package have restrictions?

Best Regards,

Kobayashi

Hi,

When the device is disabled by EN signal. The Css won't discharge to 0V if Css is too large. So it means there may be no soft start at the begining, like below waveform. SOIC pkg don't have such limitation.

Hi, Luke.
Is there difference in a discharge circuit of a SS terminal at WSON and HSOIC?

I would like to set soft-start time as 3ms, do you have any solution?

How many load at the time of waveform measurements?
I measured Css=27nF and No load, it wasn't such waveform.

Best Regards,

Hi, Luke.
Thank you. I understand.