ATTiny84/44/441/841 Minimum Common Mode voltage to differential ADC

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1

Hi guys,

Would anyone happen to know the minimum common mode voltage that can be sent to the ATTiny differential ADC? I need to measure the voltage across a current sense resistor, and so I would like to attach the inverting side of the built-in op-amp to ground - which is the low side of the sense resistor - and the non-inverting side to the high side of the resistor. With op-amps, the minimum voltage is specified as the minimum common mode input voltage, but there seems to be no such thing in the Atmel datasheet.

Thanks!

2

I think it's rail to rail.

Certainly the formula in 16.11.2 (pg 143) of the 841 datasheet suggests that, though it doesn't state it explicitly.

3

Electrical characteristics page of my 84a says (ADC differential mode) minimal input voltage is GND, maximum is Vcc.

4

Good find. Sometimes I question competence of the people who write these things.