[Review Request] Rocket Fligth Computer

[u/prynderex]

top layer

botoom layer

gnd plane

power plane

Power Plane

This is my first pcb, a rocket fligth computer. I used a 4 layer layout with Signal-GND-Power-Signal stack. I poured gnd to the top and bottom layer and stitched gnd vias. The mosfet and the terminal block for the ejection charge will be on the second board. Is this board ready for manufacturing?

Note: It's Flight* lmao, sorry for the typo

[u/Objective-Elk2093]

You didn’t appear to design for vibe

[u/prynderex → u/Objective-Elk2093]

what do you mean?

[u/Objective-Elk2093 → u/prynderex]

Tall caps, non positive locking connectors, square board with holes inline. When this goes under hard acceleration or vibe, the connectors can pull out, the cap can rip off, and the board can flex which can rip smd components off or rip the board apart

[u/prynderex → u/Objective-Elk2093]

I understand, thank you for the notes on the physical layout. In terms of functionality, will the board still work as expected despite those points? I will adjust them later to address the vibration issues, I'd just love to know whether the board will work eletrically and if the board layout is fine.

[u/Objective-Elk2093 → u/prynderex]

I’d do this in 4 layers. Your return paths are cut by traces. Your decoupling looks poor. You should relieve your pads if you’re planning on hand soldering. Can’t tell too much more without sch

[u/SmallOne312]

Just go 4 layer board with some variation on GND PWR GND fills, the cost difference should be minimal for better performance, and more stitching vias, your mounting holes are quite close to the boards edge, I'd worry about them pulling out under acceleration/shocks. Also unless you epoxy the THT cap it might break off in flight. Also you don't seem to have any decoupling caps on the MCU. Also probably worth silkscreening basically anything that would be good to know, connector pinouts, board name, component names etc

[u/SmallOne312 → u/SmallOne312]

Also test points on any important net and jumper resistirs/jumper points on anything your not completely sure on so you can rework incase you've misconnected a pin

[u/Enlightenment777]

This comment is posted on all reviews.

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Please make sure your review post adheres to:

• subreddit rules (#1 to #6), review rules (#7), review image rules (#8), see link.

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Please fix these common schematic layout issues: (if yours has any of these issues)

• Don't allow text / lines / symbols to touch each other, and don't draw lines through symbols.

• Use correct reference designators (RefDes), and renumber to remove numeric gaps, see tips.

• For positive voltage circuits, point positive power rail links upwards and grounds downwards (maybe sideways), see tips. For negative voltage circuits, point negative power rail links downwards and grounds upwards (maybe sideways). For bipolar circuits, maybe point grounds sideways.

• Place decoupling capacitors vertically below postive power rail lines with ground on bottom side of the capacitor. Place capacitor next to IC symbol, and connect a line to IC positive power rail pin, see tips and example.

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

• Reasonably minimize the use of unique net labels, because everyone hates hunting for them!! Single resistors / capacitors / diodes should not sit by themselves, instead move & connect them with a line to their circuit.

• More schematic conventions / guidelines / tips - 1, 2, 3, 4.

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Please fix these common PCB layout issues: (if yours has any of these issues)

• Silkscreen - add board name / board revision number / date (YYYYMMDD, YYYYMM, YYYY) for traceability.

• Silkscreen - add pin 1 indicator next to ICs & connectors (not under parts). For polarized capacitors, add "+" next to positive pin. If part is through-hole package, place indicator on both PCB sides. See 1, 2, 3, 4.

• More PCB conventions / guidelines / tips - 1, 2, 3, 4, 5.

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[u/KpmSmfrt]

Is your top layer pour not GND?

[u/FourtyMichaelMichael → u/KpmSmfrt]

It appears to be ground, but I think you're asking because all his caps go to via instead of plane?

EDIT: lol, no, look all his grounds are non-thermal solid connection. YIKES.

I mean, not that it applies here, but I can consider if working with really small parts you might get tomestoning if you have a lot of thermal mass on one side and only one small trace on the other? He might have read to just go to gnd plane or something? What looks like his power connector is solid and not thermal to ground. If he is hand soldering that'll be a pain in the ass with a high temp lead free solder.

[u/KpmSmfrt → u/FourtyMichaelMichael]

No direct or thermal relief connection on the JST horizontal connector, caps, TVS... But the blue through hole connectors pin 1 is ditectly connected though... He should get rid of the vias routed to the GND pads and add a lot more stitching vias.

[u/FourtyMichaelMichael]

Your solid connections to ground are a bad idea. Use thermals, definitely for hand solder, and even still for reflow.