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ADC and the 18FxxJ94

Posted: Mon Aug 15, 2016 10:16 am
by Jerry Messina
Does anyone have any experience with using the ADC in the J94 devices?

I'm having a heck of a time getting stable readings out of the thing. I'm only doing simple single channel measurements and according to the datasheet it's supposed to be capable of 200Ksps in 12-bit mode. It's acting like the sample/acquisition times are all wonky. I have to add all sorts of delays (a LOT of delay) else it's way off.

I'm using an external 2.5V reference and all of the ADC channels are buffered and driven from an MCP6031 opamp output so I don't think it has to do with the source impedance.