FPGA + A/D converter

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--Ray Andraka, P.E. President, the Andraka Consulting Group, Inc.

"They that give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Benjamin Franklin, 1759

It all depends on the resolution/speed you need. Tracking ADCs, which use a DAC and comparitor, are simple. The DAC can be single pin PWM, or Rate Multiplier - for better performance, external Vcc/Vref, and buffer all help. Gnd and Vcc lines on FPGAs are NOT low noise analog nodes !

Sigma-Delta ADCs are also simple, but need an integrator/Vref/Slice for best performance.

If it is a closed-loop system, where you are more interested in a balance-point than absolute precision/linearity, then the very simple single slope RC ramp can be used. -jg

FPGA. Is

FPGA.

Any ADC on an FPGA is going to require something externally, so why not use a cheap external ADC or a small 8 pin micro with an ADC?