### Q

could you please advise theQuiesecnt power consumption

Mean power consumption

Maximum power consumption

values for the above RDC

### A

Maximum power consumption is the simplest so let me start with that:Assuming maximum power supplies of +12V, -12V and +5V, the data sheet gives

values for the maximum current on each supply.

(24V x 23mA ) + (5V x 1.5mA) = 560mW

For supply voltages higher than +/-12V, you should assume the higher maximum

current of 30mA and recalculate the above equation.

Quiescent power consumption is not really a meaningful term for the AD2S80A

RDC. The converter is tracking converter (it continuously looks at the input

signal and uses feedback to null the error signal) and is therefore always

converting. In a Successive Approximation Register ADC, where the part is

sitting idle for most of the time consuming very little power, and only

consumes power when you request a conversion, quiescent current is meaningful.

In a tracking converter, the part never goes into a low power mode.

It is true that if the input shaft is idle and not turning, the part will

consume less power than when the input shaft is turned sharply to a new angle

and the converter must slew to the new angle consuming more instantaneous power

as it does so. However this is a dynamic effect and has not been characterized,

indeed it would be difficult to do in meaningful way and in any case the

difference in power consumption will be minimal and any effect should be

mitigated by power supply decoupling.

A similar argument will apply to average/mean power consumption. We do include

typical power specs on the datasheet, but these refer instead to differences in

power consumption due to part to part variation rather than power consumption

differences due to different operating conditions.

In short I suggest using the maximum power consumption throughout in your

calculations and assume that the power dissipation is essentially constant.

This will slightly over estimate the power consumption for most applications

but is has the benefit of being guaranteed by production testing.

One final word. You will also see a maximum power dissipation spec of 860mW in

the Absolute Maximum Ratings on page 5 of the datasheet. This refers to the max

power dissipation allowed by the package and is not an indication that the

AD2S80A will dissipate this much power under normal operation.