ADC and DAC power requirements

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engr_joni_ee

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I am wondering how do we make power budget when we have ADC and DAC in the schematic. The operating voltage of the ADC and DAC usually clearly written in the datasheets but how much the power supply current is the main question in this post.

As an example consider the following two.

ADC: AD7291BCPZ
DAC: MAX5541ESA

How much the maximum current these two chips can take from the power supply.

In the datasheet of ADC: AD7291BCPZ, Isink is mentioned as 6 mA but in the power requirement table, the current 3.5 mA is mentioned as "Normal Mode (Operational)". The datasheet also says "Input Current to Any Pin Except Supplies = +/-10 mA". I guess 10 mA is not the power supply current so should not be used in power budget. So, the current 3.5 mA is the power supply current to be used in power budget ?

In the datasheet of DAC: MAX5541ESA, the positive power supply current is 1.1 mA. The maximum current to any pin is mentioned as 50 mA. So, the power supply current 1.1 mA is the one that should be used in power budget ?

Link of datasheets
https://www.analog.com/media/en/technical-documentation/data-sheets/AD7291.pdf
https://www.analog.com/media/en/technical-documentation/data-sheets/max5541.pdf
 

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ADC and/or DAC commonly make use of weighted resistor networks (which represent bits in binary language). Current is switched through one or more resistors based on whether bits are hi or lo. Overall Amperes can vary over a large range. You might need to examine whether the IC sources current at certain terminals or sinks current.
 

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That's true.
But still, if we do not need precise analysis. is there any reasonable number for current that we can safely put for power budget.
 

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We know the supply voltages. The power in mW can be calculated by multiplying voltages to current.

The currents are very small.

Is there any other current other then mentioned above in #3 and #4 that I need to consider for the power budget for both chips ?
 

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