LM5117: LM5117 datasheet inquiry

Hi,

I don't think LM5117 has a specific difference on SW transient and SW rating, so please follow SW to AGND rating as datasheet describes. Thanks.

Hi Iven:

1.Will Undershoot voltage -3.8V affect the IC?

2.If yes, are there any solutions to improve Undershoot voltage?

Thank you so much

Hi Iven

The customer measures the waveform of Undershoot results.Can you help suggest ways to improve?

線路圖.pdf

Hi Ivan

The test results are as below , Any other suggestions for improvement

1) According to your suggestion, C6 & R16  removed as below no improvement.

2) R16 = 1 ohm, C6 = 10000 pF can be improved as below , but the High Side NMOS temperature rises 20 degrees

OK, I see, could you please change to larger R41 and R42? Also, how is your layout of QM1 and QM2? Is the SW trace very short?

Hi Ivan

Why do I need to open the BWL on the LM25117 EVM board when testing the SW voltage?

https://www.ti.com/lit/ug/snva469b/snva469b.pdf?ts=1591611382677&ref_url=https://www.ti.com/tool/LM25117EVAL?keyMatch%3DLM25117EVAL&tisearch=Search-EN-everything&usecase=GPN

Hi,

What do you mean by BWL? You could test SW at any proper setups. Thanks.

 We see your test (EVM) is under BwL condition (limit bandwidth in 20MHz). Our customer has concern because they see different result in BwL and full-bandwidth.