LM25149-Q1EVM-2100: Changing output Voltage to 12V

Thank you for your support.

In this calculator, I could not get MPN for 12V output, also in datasheet too, is there a place that I can check for it?

Hi Betul,

Can you please show what you mean by "could not get MPN for 12V"? 

Thank you,

Joshua Austria

Hi Joshua, when I change output to 12V on  design calculator, which Mosfet should we use, should we use still same Mosfet with LM25149-Q1EVM-2100? Thanks...

We remove all you say, still no output, and LM25149 is getting warm.

Hi Betul, 

Can you please do an ABA swap? With a fresh unit? The one you have used may have been damaged. 

Were there any other changes made to the board? What are those resistors on those pins?

The EVM MOSFETs should be fine for 12VOUT.

Thank you,

Joshua Austria

Betel,

Just to add more info here: VCCX is tied to VOUT for a 5V output. Changing to a 12V output means VCCX should be disconnected and tied to GND (otherwise there is an overvoltage on VCCX). As this EVM is set for 2.1MHz at 5Vout, you'll need a higher buck inductance for 12Vout. Check the output caps and loop compensation as well. Take a look at the LM5149 12Vout EVM for reference.

--

Tim

Hi Timothy, we already remove R10, and connect VCCX to GND by R14, we even do not connect anything, but still cannot get voltage, we try this in 3 different EVM.

We connect 0R resistor to R14, remove R10
Remove R20 and R22 connect 49K resistor between FB and VDDA. 

It is not complicated, so please help if anything should I do. Thanks.

Hi Betul,

Please send a completed quickstart calculator for this design. Did you adjust the inductor, output caps and compensation for 12Vout?

Regards,

Tim

Hi, we do not change any other components on  LM25149-Q1EVM-2100, some guys here said only thoose should be enough, so we do not change or adjust any  inductor, output caps. What you mean by compensation for 12Vout?

What you mean by this "send a completed quickstart calculator for this design", we already using LM25149-Q1EVM-2100.

Thanks for your support.

Hi Timothy, https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1532440/lm25149-lm25149-q1-evm-verify?tisearch=e2e-sitesearch&keymatch=lm25149%252012v#

in this post, it says working, this is why we are trying. They said changed nothing else thoose.

Should we design 12V output regulator with LM5149 EVM schematic and only change IC to LM25149?

Thanks.

Hi Betul,

In the post linked, there is no indication that a schematic was shared or a design was recommended. Do you have a different thread that you are referring to instead?

In either case, the design calculator will still need to be used to rework your inductor, output capacitors, and compensation as these will all need to be modified when changing from the default 5V BOM of the EVM to the 12V that you are trying to achieve.

Thank you,

Joshua Austria

Okey, thanks for your support, if I share schematic can you check it? Thanks for your support?

Hi Timothy, thanks for your support, maybe I disturb you so much, can you check our schematic, and BOM, thanks for your help.LM25149.pdf

Hi Timothy, I already attached PDF. Let me share it again.

1172.LM25149.pdf

Please send a completed quickstart calculator file as well.

Hi Timothy, it is also attached now. thanks for your support.LM5149_LM25149_quickstart_calculator_A4.xlsm.zip

Thanks, Betul.

I'll take a look and reply tomorrow.

Regards,

Tim

Hi Tomothy, just to remind you, thanks.

Hi Timothy, sorry for confusion, we send wrong calculator, sorry about that, can you please check this?

Regards...
LM5149_LM25149_quickstart_calculator.xlsm.zip

Hi Timothy, is that enough to apply those schematic to our design? Thanks.