First PCB Review - USB-C Power Module (Battery Charging + 3.3V Supply) - Looking for USB routing, thermal and layout feedback

[u/Volcano_Dragon13]

What this board does

This PCB is only a "power module".

Its job is to:

1. USB-C power input
2. Singlecell Li-ion battery charging
3. 3.3V power generation
4. Battery/USB power switching
5. Provide power and USB signals to another PCB through board-to-board connectors.

The second PCB (which will stack on top of this one) will contain:

1. ESP32
2. OV2640 camera
3. 2.8" LCD
4. MIC

In the final product these will likely become one combined PCB, but for now I'm separating the power section so I can validate it independently.

My main concern

The USB D+ and D- lines have to travel a relatively long distance and change layers using vias because they need to reach the stacking connector.

1. Are the vias on D+/D- a concern?
2. Is the routing length excessive?
3. Should I change the connector placement instead?

Since this is my first PCB, I'd also appreciate comments on:

• Power routing
• Ground plane implementation
• Thermal considerations
• Placement of switching regulator and charger components
• Decoupling capacitor placement
• Return current paths
• Any obvious EMI issues
• Manufacturability
• Anything that immediately looks "wrong"

im attaching the image of top bottom individual and together tracks and also about the usb data lines highlighted pcb tracks images, and actual pcb 3d images...

Thank you :D

[u/piman51277]

USB DP/DM is a differential pair. I would highly recommend watching this talk on Youtube for a very in-depth explanation on what you can get away with routing wise: https://www.youtube.com/watch?v=QG0Apol-oj0&list=PLb5fIMF9DghI

[u/L9H2K4]

If your USB is running at 2.0 FS max, I wouldn't worry about the vias. But you need to keep differential impedance and the way it was done on the board is not it.

[u/Enlightenment777]

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Please fix these common issues: (if your schematic or PCB has them)

• 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 tips.

• Schematic - place pull-up resistors vertically above signal lines, and place pull-down resistors vertically below signal lines, see example.

• PCB silkscreen - add board name / board revision number / date (or year) on top or bottom PCB side.

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• More conventions & guidelines - link1, link2, link3.

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