LMR38020: Output power lower than expected

Abigail Leonardi

Part Number: LMR38020

Hi,

I'm expecting to have 15V on the output on the LMR38020 but I'm seeing the following output where the voltage is around 2V.

Any insight on what may be the issue? Thank you.

over 1 year ago

0 Ben C over 1 year ago

TI__Guru 56345 points

Hi Abigail,

Can you tell me a little more details about your setup? What is the voltage at VIN?

Ben

0 Abigail Leonardi over 1 year ago in reply to Ben C

TI__Expert 3510 points

The reference design with the setup can be found here https://www.ti.com/tool/TIDA-010950. The yellow line shows the VIN voltage, we are inputting 20V and expecting 15V out

0 Ben C over 1 year ago in reply to Abigail Leonardi

TI__Guru 56345 points

Hi Abigail,

Can you measure the resistance of R29? A 10Kohm resistor will give you an output voltage of 2.4V.

Ben

0 Ben C over 1 year ago in reply to Ben C

TI__Guru 56345 points

Hi Abigail,

Are there any updates?

Ben

+1 Abigail Leonardi over 1 year ago in reply to Ben C

TI__Expert 3510 points

The resistor is the correct value, I think we may be shelving the issue for now. We found a possible contributing factor due to the power planes being split on the PCB that we are looking into.

Thank you for your time.

0 Ben C over 1 year ago in reply to Abigail Leonardi

TI__Guru 56345 points

Hi Abigail,

Thank you for the update. Can you please close the thread by clicking on "resolved? Thanks,

Ben

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LMR38020: Output power lower than expected