LMR16030: Output is 400mV decaying over time to around 340mV.

hi, Kevin,

It look like the device is not swtiching and generate the right output,

please remove C12 and make sure the EN is connected , 

we provide a hardware demo could required online, please take this SCH as a reference first. 

https://www.ti.com/lit/ug/snvu496/snvu496.pdf?ts=1663293313197&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLMR16030

Elena

I removed C12 as you suggested and shorted EN to VIN, yet the output does not appear to have changed. The output still begins at around 400mV then slowly decreases to 340mV.

hi, Kevin,

please share your test condition ,like Vin Vout Iout, I have compared with SCH of EVM ,mot much issue in your design. please double check all the component is solder good, inductor is not open ,and Vin Vout is not shorted, test Vin to GND and Vin to SW diode, ensure the IC is connected. If still can't work suggest to upload you PCB layout for review.

Elena

I'll upload my PCB layout.

I've tested:

10V < Vin < 32V

Vout ~ 0.4V

Iout = 100mA

I've ensured that all solder connections are good and made duplicates of the board with individual modules, all of which show the same problems.

Link to file: drive.google.com/.../view

hi，Kevin，

could you give me a screen capture of the PCB sorry we are not allowed a kicad installed ,only AD for PCB design.

Also, could you have some waveform ,that's will be helpful. L2D2 current is fulfil.

another question is, is this IC purchase from TI or other agent. just to confirm if all of you board is not working. 

Elena 

What's more , you can request a free EVM online ,and do a ABA test on different board, ensure it's not a hardware issue.

Elena

Here's the screen capture of the PCB, using three of the ICs for multiple outputs.

I don't know what you mean by L2D2 current.

The IC purchase was from Mouser. I would certainly be interested in requesting a free EVM, but I do not know how long that process would take.

The layout look not very suitable for a DCDC , I have a reference here 

here is the EVM request page, please login and better with your company email.

https://tisamples.ti.com/orderable-part-details/product/en-us/LMR16030PEVM/part-details/LMR16030PEVM

I understand that it looks very different from the reference board, but what in particular looks unsuitable? I do not see what could cause the IC not to switch.

I will check within team and give you a update next my work day.

hi, Kevin, 

Thank you for waiting, i have check with in team and ,could you try on the 5V rail on the right side of you board, like Vin=12V ,no load, please double confirm the diode is right connected, 400mv is very like a diode voltage drop . and please also share the diode part number .

Elena