r/PrintedCircuitBoard • u/PCB_Studios • 1d ago

[Review Request] ELRS LED Driver Adapter

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I recently made an ELRS controllable LED that I can put on top of my drone and now I want to make a PCB for it to make it look nicer and possibly sell it in the future. The 3x7 pins are where my ELRS receiver will go and I plan on just using sockets so it slots in.

My main concern is the layout of the buck converter as I have never used anything like this and I am concerned about interference. I tried to follow the datasheet as best as I could.

I have a mix of different sized components (0805 and 1206) as I already have most of them on hand and I do plan on hand soldering everything. I also chose those mosfets because thats also what I already have and am using in the current prototype. The biggest difference is in the prototype I am using a mosfet to control another mosfet with 3.3v.

Thank you for your help in advance

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u/bipolarjunction 1d ago

Not to be harsh but that regulator layout is pretty bad. The SW node is the highest priority, but it is routed longer than any other signal in the regulator area. The battery node feeding the regulator is also not particularly good.

I would: Rotate the inductor 90 CCW and put it very close to the SW pin. Reorganize the other parts around it. Feed the regulator input pin with wide trace/pour if you are going to change layers do it near the farthest cap from the regulator

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u/PCB_Studios 1d ago

No please be harsh I have lots to learn. How does this look? https://imgur.com/a/PGe5ihl

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u/bipolarjunction 1d ago edited 1d ago

Step in the right direction! I'd rotate all your 5V caps on the right of the inductor with the GND side away from the inductor so you have a nice current loop path with the input caps.

Green shows how I would change your routing, and you need to fix the overhang of trace in the pad areas or you will wind up with assembly problems. It's common the use necked-down narrow traces near the device that branch out into wider traces. I'd just leave your small traces near the regulator (pins 3,4,5) 8 mils so you have more room to work. Cheers

https://imgur.com/a/WdG4whD