Getting your first PCB to power on: a pre-order checklist

The worst time to find a board mistake is after you’ve paid for it and waited two weeks for shipping. Here’s the checklist we run on every first-revision design before it goes to fab — most of these catch the failures that turn a first board into a paperweight.

Power

• Decoupling: 100nF right at every IC power pin, short trace to ground.
• Bulk cap at the power input, plus bulk near anything with current spikes (MCU + radio).
• Reverse-polarity protection if a human plugs it in — at minimum a series diode, better a P-FET.
• Right regulator: rated for the peak current, not the average. Add headroom.

Boot and reset (microcontrollers)

• EN/reset with the recommended pull-up + RC delay so it powers up cleanly.
• Strapping pins in the correct state at boot — the #1 cause of “it powers but won’t program.” On ESP32-S3, watch GPIO0, 3, 45, 46; on the N16R8 part, leave GPIO35/36/37 for the octal PSRAM.
• Programming header wired and accessible.

External IO

• ESD protection on anything that leaves the board — USB, connectors, buttons.
• USB-C: 5.1k from each CC pin to ground (two separate resistors, never one shared).

Make it debuggable

• Test points on your main rails and a couple of key signals. You will thank yourself when it doesn’t boot first try.
• Silkscreen labels on connectors and headers.

Mechanical

• Mounting holes placed and clear of components.
• Ground pour stitched with vias so no copper island floats.

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Run this before you hit “order.” It’s ten minutes that saves a board revision and a deadline.

Doing a thesis or product build and want a second set of eyes on the schematic before you fab? Send it over.