PCB DFM Pre-check Checklist (run through it before you release the layout)
Zhixin Heng Electronics - PCB Solution Design

How to use: go through this list before the layout starts. If you cannot answer
one of the items, the design is still missing information. Align with the engineer
first, then start - it saves a whole round of prototype rework.

1. Stackup and impedance
[ ] How many layers, and which ones carry signal versus power/ground planes?
[ ] Are impedance targets written down? (single-ended / differential / other)
[ ] Are dielectric thickness, laminate type and copper weight specified?
[ ] Do you have the fabricator stackup table? (available stackups differ a lot)
[ ] What impedance tolerance is required?

2. Signals and interfaces
[ ] Which high-speed interfaces are on the board? Data rate, protocol, length matching?
[ ] Any external clock, crystal or reset signal? Active or passive?
[ ] Are differential pairs assigned an impedance and a reference plane?
[ ] Any analog, RF or high-voltage areas that must stay isolated?

3. Power
[ ] How many power rails? Voltage, current, ripple requirements?
[ ] Any high-current traces? (above 1 A usually needs its own copper and thermal check)
[ ] Any power-up sequencing requirement? Inrush or soft-start requirement?
[ ] Switching or LDO regulators? What switching frequency, and how far from sensitive signals?

4. Mechanical and process
[ ] Board outline, thickness, cutouts, radii and slots all defined?
[ ] Mechanical interference checked against the enclosure? Connector mating position correct?
[ ] Mounting holes, tooling holes or shield cans to be reserved?
[ ] Any component height limits? Parts that need manual assembly?
[ ] Two-sided assembly? Orientation of bottom-side parts?

5. Assembly and process
[ ] Do you have the fabricator minimum trace/space, drill size and solder-bridge rules?
[ ] BGA ball diameter and pitch? Is there enough escape routing space?
[ ] Panelisation required? Panel style and process-edge requirements?
[ ] Surface finish: ENIG / HASL / immersion tin?
[ ] How many impedance test coupons are needed?

6. Test and manufacturability
[ ] How many test points are needed? Any placement constraints?
[ ] Boundary scan required?
[ ] Any signals that need a production test fixture?
[ ] Does the BOM specify approved alternates, and which parts are critical?

7. Commercial and coordination
[ ] When do you expect the prototype files?
[ ] Do you have a fixed PCB or assembly house? If so, send us their specification.
[ ] Any required file formats? (Gerber revision, coordinate format, assembly drawing format)
[ ] Who talks to the fabricator after handover?

-- Zhixin Heng PCB Solution Design - Technical Support