ADS8320: Power consumption at 400Hz

Hello,

In the ADS8320 datasheet, Figure 23 refers to error measurement test results, would you clarify which graph you are refering to that displays the power consumption.

The power dissipation of the ADS8320 scales directly with the conversion rate, thus the lower the sampling rate the less power consumption the device will dissipate. But you are also correct that the device will hit a static power consumption as it does need a basic level of energy to operate.

The cover sheet states that the device will dissipate 0.3mW at 10kHz with a Vcc of 2.7V, I predict this is when the device is in power down mode. In the electrical characteristic table, at Vcc=2.7V, it states that typical 1.8mW power dissipation at sampling rate of 100kHz is expected. Thus, that gives an idea of the minimum power consumption expected from the device.

At sampling rate of 400Hz you should experience a lower linearly scaled power consumption than expected at a sampling rate of 1kHz, but I do not believe it will be a perfectly linear relation when hitting lower sampling rates.

You can increase your power savings by taking advantage of the power down mode, as well as using the lowest Vcc supply your aplication can support. Other details on this can be found in section 10.3 of the datasheet.

Regards, Cynthia

Cynthia,

Indeed I made an error. It’s figure 36 that’s I meant. In the description it says that if you run the clock at a 2.4MHz rate but only convert at 1kHz it can go as low as ~7uA *  2.7V. My question is whether this curve scales further as we go down below 1kHz.

Thanks,

Renaldi