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| how to route codec (ADC/DAC), analog pins not all on one side |
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| capt bullshot:
If there's more than 2 or 3 power rails that you can't divide into planes with a few simple sketches, I do prefer to run traces as wide and as short as possible, then pour copper of the respective potential around the traces, with the result similar to planes (little non-copper area left). Your component placement should keep the components running off a particular rail together, so in the end result it'll look like a split power plane. Keep the goal in your mind: GND and supply distribution shall be low impedance. Regarding the thermal pad paste: One big aperture may work, often an array of 4 to 9 equally spaced apertures is used to improve production yield - ask your EMS for best results and experience. |
| thm_w:
Routing looks so much better now. --- Quote from: mrjoda on October 23, 2019, 08:33:03 am ---Hi, avoid the acute angles, it's called Acid traps (google some PCB layout guidelines). I do not like the routing of 3V3VA to oscillator. I would not share one capacitor and one trace with power pad of chip. Otherwise it looks better than in previous case. --- End quote --- Doesn't matter. For the 3v3, there are three caps in that area, probably not ideal but will work. Although if that purple line is the 3v3 power trace going off, I would fatten that a bit, no reason to have power trace so thin. |
| loki42:
Do you mean the acid traps stuff doesn't matter? I've seen a few people say it hasn't been an issue for a decade or two. What would be ideal for the 3v3 cap wise? Oh and there are planes where ever there are power traces so I've made that trace big now to make that more obvious, as @capt bullshot suggested. I'm not sure if I need to use anything more snazzy than an LM358 to buffer VCOM. I given it's buffering the reference any noise in there will couple directly but I'm not sure if the level with no gain is an issue. |
| mengfei:
what's with the weird traces? like those below U4 which should have all been straight? what software are you using? if possible get supply directly from the supply line like the last output cap & not share all on a single rail "IF" possible acid traps are corners where chemicals can be well trapped ;) your lucky you can work with multi layer boards while I'm still doing single side boards for SMPS, PTH + SMD's |
| loki42:
The ones under U4 just become the ground plane, if you look at the image with the planes. |
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