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Recreating mod chip designed for the Playstation 1.
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Katcher:

--- Quote from: KL27x on November 05, 2018, 07:00:29 pm ---Don't make the pads so big. Bigger != better. The size of wire you are going to be soldering to them is probably 30AWG solid. The pad you want is maybe 50 mil by 50 mils. If you have extra space, you are better served to turn it into extra clearance around the pads. If for no other reason, this is easier on your eyes when you install it. Looking at a sea of shiny solder blobs, it is taxing to try to see a tree for the forest.

Also in this square design, you have no clearance between pads and traces. This is bad. The soldermask is not going to perfectly align with the copper, and the default soldermask opening is slightly larger than the pad*; you can make a board where you can solder a wire and the end of the wire ends up touching the edge of the trace or plane that is running alongside, peeking under the misaligned soldermask.

Around hand solder pads, I try to make clearance at least 20 thousandths on a rigid board, and I like even more if there is unused space. 

*If your software allows to change the size of the soldermask, and you wanted maximum strength of the pads to reduce risk of delamination through multiple reworking, you could make the pads as large as possible but leave the soldermask openings the aforementioned 50 mil by 50 mils. But not all software allows for that.

--- End quote ---

Scotsman here. Not a chuffing clue what mils are. I work in mm. The pads I have are 2x2mm. If that does seem too large I could probably set them to 1.5x1.5mm. Trace width is 0.300mm and I'm not sure what making them thinner might affect. I agree that my trace clearance is shitty. I'm actually in the process of trying to clear it up.
KL27x:
A mil is a thousandth of an inch. 50 mil is 1.27mm
KL27x:
Another tip, here. If you are going to have this fabbed, 2 layer board costs just about the same as a SS board. So you can play with vias and whatnot if that makes your pad arrangement more logical (less crossed wires over the top of the pcb when installed. In fact, you could put the pads on the bottom and glue the chip side to the motherboard to make the board dimesions even smaller.*

Also, the thickness of the FR-4 for a board this tiny does not need to be the standard size of 1.6mm. A 0.8mm board would be plenty rigid enough.

*If you wanted to put a silkscreen on the bottom, I would redesign the board so the bottom is the top. And the chip is on the bottom. Manufacturers like the silkscreen to be on the top layer.
Katcher:

--- Quote from: KL27x on November 05, 2018, 09:29:24 pm ---A mil is a thousandth of an inch. 50 mil is 1.27mm

--- End quote ---

Okay so I've changed the pad size from 2x2mm to 1.5x1.5mm and I'm in the process of re-tracing everything. I'm sticking with 0.300mm thick traces to save potential headaches. I have the decoupling capacitor connecting to pad 1 and pad 8. Pad 1 connecting to the VDD pin on the IC and Pad 8 to the VSS pin. Is there a better way to connect them together. Like connecting the pads to the pins as is but connecting the capacitor to the appropriate traces or vice versa?




--- Quote from: KL27x on November 05, 2018, 09:35:47 pm ---Another tip, here. If you are going to have this fabbed, 2 layer board costs just about the same as a SS board. So you can play with vias and whatnot if that makes your pad arrangement more logical (less crossed wires over the top of the pcb when installed. In fact, you could put the pads on the bottom and glue the chip side to the motherboard to make the board dimesions even smaller.*

Also, the thickness of the FR-4 for a board this tiny does not need to be the standard size of 1.6mm. A 0.8mm board would be plenty rigid enough.

*If you wanted to put a silkscreen on the bottom, I would redesign the board so the bottom is the top. And the chip is on the bottom. Manufacturers like the silkscreen to be on the top layer.

--- End quote ---

I've tried using vias and can't seem to get them wired right so I'm just going with traces on the top layer. As for board thickness I'm settling on 0.6mm though if that's not gonna be rigid enough I'll go for 0.8mm.
KL27x:
OK, well, if you are using the full featured PCB CAD, you typically "route" your traces rather than drawing wires. You change layers while routing and the via automatically appears. But if you're just drawing copper wires, then I guess it can be trickier.

Another tidbit, here, and a bit of a pet peeve. Complex routing looks cool, but on a tiny board like this, the routing creates a considerable kerf. If you left the board rectangular, V-scoring would save a bit of money in higher volumes.
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