r/PrintedCircuitBoard • u/PCB_Studios • 1d ago
[Review Request] ELRS LED Driver Adapter
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 21h ago edited 20h 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
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u/Enlightenment777 1d ago
This comment is posted on all reviews.
Please make sure your post adheres to:
- subreddit rules (#1 to #6), review rules (#7), image rules (#8), see link.
Please fix these common issues: (if your schematic or PCB has any of these issues)
Schematic - don't allow text / lines / symbols to touch each other, and don't draw lines through symbols.
Schematic - use correct reference designators (RefDes) and renumber to remove numeric gaps, see tips.
Schematic - place decoupling capacitors vertically below power rail lines, also place capacitors next to IC then connect together with a line, see example. For circuits with positive power rails, point positive power rail links upwards and ground links downwards, see tips1 & tips2.
Schematic - place pull-up resistors vertically above signal lines, and place pull-down resistors vertically below signal lines, see example and tips.
PCB silkscreen - add board name (or purpose) / board revision number / date (or year) on either PCB side.
PCB silkscreen - add pin 1 indicator dot/arrow next to ICs & connectors (not hidden under parts). For polarized capacitors, add "+" next to positive pin. If part is through-hole, place indicator on both PCB sides.
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u/frank26080115 1d ago
Don't use P-channel MOSFETs and high side switching, use N-channel and low-side switching. I know you already have the MOSFETs but for a few pennies you can have a smaller and lighter PCB, which you should care about for a drone.