I'm looking to build a low cost circuit for measurement of DC and AC voltage and current with resolution of about 12-14 bits. The reference voltages for the processing circuit and test circuit may or may not be same, which means that using the microcontroller's ADC is not possible, and an isolator is needed in between. The microcontroller can then receive this signal digitally (SPI etc.) or any other solution is also feasible. The number of components required is not an issue here, however I am looking for a low cost solution. I have arrived at these possible options:
1) ADE-7912: Isolated ADC, with isolated power supply inbuilt, digital serial interface
2) AD7792 (ADC) with ADuM5401 (Quad channel isolator with isolated power supply inbuilt)
3) AMC1200 (Isolated amplifier) with microcontroller ADC and an external isolated power supply (using any isolator IC)
Which solution should be preferred? More importantly, is there any easier way to accomplish this particular task.