DC-DC Switching Regulator design

[htdave]

Hi Everyone,

I have a project where I need to convert 12VDC down to 3.3V. Maximum current draw on the output will be about 150mA.

This is my first PCB design and build, so I was going to use JLCPCB to build and assemble the PCB.

The only suitable regulator that JLCPCB seem to have decent stock of is the TPS5403DR - https://www.ti.com/lit/gpn/TPS5403.

From the data sheet, I have worked out most required capacitors, resistors and inductor, but I can't seem to find any mention on how to calculate the values for Rc and Cc on the Comp line.

Does anyone have any suggestions on how to calcuate Rc and Cc?

I am also open to suggestions on different DC-DC regulators, or even a different PCB company.

Thanks

[LarryD]

Remember to use the suggested foil pattern they offer you.

[jremington]

@htdave

This is my first PCB design and build

Unless you follow the chip maker's specifications and recommendations VERY carefully, this is likely to fail. DC-DC converters, like RF circuits, are technically very challenging, tend to misbehave and are difficult to get right.

A much safer and more reliable option is to take a tried and true design, like this one, and simply mount it on your PCB.

[gilshultz]

Try this link, they are less then the parts you will need to build one. https://www.aliexpress.us/item/2251832847999601.html?spm=a2g0o.productlist.0.0.77d61243JaLKeC&algo_pvid=d4acece8-ccea-41d1-8b08-118edb7570e3&algo_exp_id=d4acece8-ccea-41d1-8b08-118edb7570e3-2&pdp_ext_f={"sku_id"%3A"67252623925"}&pdp_npi=2%40dis!USD!0.85!0.73!!!!!%40210318c216699479558492787ee210!67252623925!sea&curPageLogUid=6eD7EkPWEqyE

[johnerrington]

I agree with @jremington and @gilshultz - dont mess about, mount a module on your pcb.
Easy to replace if there is a problem.

[JCA34F]

I like these, not cheap though.
https://www.digikey.com/en/products/detail/murata-power-solutions-inc/OKI-78SR-3-3-1-5-W36-C/2259780
https://www.murata.com/products/productdata/8807037992990/oki-78sr.pdf?1613964620000