LMR50410-Q1: Schematic & Layout review

Hi Kygo,

I filled out the Calc tool for TPS54360, and it's telling me your inductance is too small for U2.

https://www.ti.com/lit/zip/slvc452

The ripple current may be larger than you want which could mean larger ripple on the output. You could probably get away with using a 3.3uH for this application as the peak current won't cause the device to hit current limit, but I'd like to clarify something first.

Is the 12V input voltage the max voltage the device will see? 

The calc tool is recommending that we use a 6.8uH inductor for L3.

Everything else looks good.

Thanks,

Andrew

Hi Andrew 

Thank you for your comment! I will suggest RD use a 6.8uH inductor for L3! 

Do the LMR50410-Q1  & TPS54360  also good ? THX             

Hi Kygo,

They are good. You could technically use a 3.3uH inductor (Either smaller part or lower DCR) for the LM501410-Q1, but the 4.7uH should work.

Thanks,

Andrew

Hi Andrew 

May I know that which inductor should I suggest to RD? 3.3uH or  4.7uH or 6.8uH?  THX

Hi Kygo,

I haven't heard from you in a while.

I'm going to assume this issue is resolved.

Thanks,

Hi Andrew 

Thank you!

Now we DIN our device , I am waiting for customer's first version test ,THX

Hi Kygo,

Have a great day!

Feel free to follow up on this thread if the customer has an additional comment.

Thanks,

Andrew

Hi Andrew

We have issue for  TPS54360 now!

Test condition : input is 12V / output is 5V &  no load

R41 is open now ,so disconnected from the back end now

I measured the capacitor C13 at the output end and found that there will be a platform as shown in the figure below when the power on .

Is it a parametric design problem? For example, feedback...
Please help to give some possible root cause and solutions,THX

Hi Kygo,

Could you share how EN and VIN are ramping with respect to VOUT? I would also like to see the switching waveform to see if any funny business is there.

Does anything different happen when you load the circuit?

Thanks,
Andrew