Quote:
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Originally Posted by Groth
Separate digital and analog ground is probably unnecessary, since the internal ADC convertion clock (1.7 MHz) is much higher that your comms clock (~1-10 KHz) and your sample rate (10 Hz?). If you really want 'em separate, use the p-port ground as your digital ground and your power connector solely analog.
Plane: yeah, cool if you can. I'd try to lay everything out as a single sided board (easier to home make) and then use the other side as a ground plane.
What sort of through-hole to surface-mount ratio are you going to have?
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Well, as it is evolving the board will be two sided. I will probably use the ExpressPCB service. I can see that there is no way I am going to be able to lay this out by hand and keep a decently small board.
As it is so far I am managing to keep the bulk of the analog stuf on on side with a few power and digital lines on the other. This means there is a fair bit of room for a ground plane.
The only surface mount stuff are the opamps and the instrumentation amps.
Have a gander at the current unfinished but nearing completion state of things. Right click and save target.
Circuit and
pcb. You need the ExpressPCB software to view it and feel free to be critical.
Not pretty, I am not giving up my day job. I decided to try the layout for size before seeing if I could incorporate a PWM generator in the available "miniboard" space. It will probably work, I will at least put the traces in.