Power Consumption between ADAU1701 vs. ADAU1761

Hello Ron,

Power consumption is a measurement of energy conversion equal to 1 Joule per second, which is also equivalent in electrical terms to the rate of Work of 1 Ampere flowing through a potential difference of 1 Volt. By extension, a milliwatt (mW) is a measurement of 1 mA flowing through a potential difference of 1 V. A common equation to describe this relationship is Power = Current x Potential Difference, or P = I x V. So, to answer your first question, the measurement is not mW/hour, but simply mW. The relation to time is already included in the unit: 1 mW = 1 mA x 1 V = 1 mC x 1 V / 1 second. NOTE: mC = milliCoulomb.

I assume you are interested in the power dissipation spec because you'd like to conserve battery power in a portable application. A more appropriate metric for computing battery life would be current, measured in mA.

The ADAU1701 datasheet shows a power dissipation between 118 and 287 mW, and has a supply voltage of 3.3 V. From this information, we can calculate the current as follows:

Power = Current x Voltage

(118 ~ 287)mW = Current x (3.3 V)

Current = (36 ~ 87) mA

Assuming the worst case of 87 mA, you could run the ADAU1701 for about 2 hours with a 120mAh battery.

The ADAU1761, on the other hand, which can have current consumption as low as 6 mA in some modes and supply configurations, could run on the same battery for up to 20 hours.

(this is of course conditional on the operating mode and supply configuration of the ADAU1761 in your system, as well as the current draw of other ICs and passives in the system)

The current consumption can differ greatly depending on many system parameters, including supply voltages, register settings/modes in the IC, interfacing to external ICs, etc... Therefore, it is very difficult to give a single power consumption number for an IC in the datasheet.

If you look at Table 4. in the ADAU1761 datasheet (Rev. 0), you will see that the AVDD supply current can vary from 5.73 mA to 11.33 mA, depending on different modes of the IC. Also, the IOVDD supply current will vary depending on external interfacing and if the IC is in master or slave mode on the serial port.

Also, if you look at table 3 of the ADAU1761 datasheet (Rev. 0), you will see that the current consumption can vary from 2 mA to 56 mA depending on many factors such as supply voltage and operating mode.

Overall, the ADAU1761 is much more efficient than the ADAU1701, which is why we label it as a "low-power" SigmaDSP. However, it really depends on your specific application and settings. The best way to judge how much current your system will consume is to evaluate it on our SigmaDSP evaluation boards.

To answer your question about power consumption modes:

The ADAU1761 has several power-saving modes, and subsystems of the chip can also be deactivated when not in use to conserve power.

The ADAU1701 has no special power-saving modes, but some subsystems of the chip can be deactivated when not in use to conserve power.

This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,
EZ Admin