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# ADC081C021: Power consumption in automatic mode

What's the power consumption in the Automatic mode for the higher Conversion Intervals? The datasheet mentions only the power consumption for the highest sample rate.
What is the power consumption for the lowest sampling rate and for other sampling rates?

• Hello,

The available information about current consumption is available in the datasheet.

the sample rate and consumption are related, the faster sampling rate, the more power consumption.

Given the two top graphs, I would suggest using the equation given Fsample =Tcon*32 on the right graph, to relate to the power  consumption based on the left graph. The data on the right graph seems to be the max power consumption, in automatic mode

Regards

Cynthia

• Hey Cynthia! Thank you for the answer.

One is not able to compute the power consumption basic on the graphs because they don't depend on the sampling frequency. The graph says explicitly that it "some physical quantity" vs the supply/reference voltage.

The left-top frequency that changes is the clock frequency of the bus, not the sampling frequency.

Unfortunately, that did not address my question correctly.

I am aware that the power consumption will decrease for lower sampling frequency. The question is how much will it decrease? I would assume that the supply current can be given with such an equation:

I = I_idle + I_conv

Where the I_idle will be the supply current not related to the analog-to-digital conversion itself, but some background current needed to supply some internal circuitry; and the I_conv is strictly dependent on the analog-to-digital conversion sampling rate. So the question is, in other words: what's the ratio for I_idle to I_conv?

• Hello Kacper,

Yes, some estimation will need to be used to get an idea of what the consumption would be based on the information available.

The data sheet provides the below information relating the clock rate and the conversion rate, you could use this.

As for the relation between idle current and conversion current, these are usually not related. The idle, or operating current of the device tends to remain consistent and a minor part of the current consumption. The bulk comes from the analog converting operation. Thus sampling rate and VA are usually the biggest factors.

Regards

Cynthia