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ADS1118: Power dissipation under the other condition.

Motoyasu Hattori
Genius 11005 points
Part Number: ADS1118

Hi, team,

Please advise me how to calculate power dissipation under the following condition?

 

　VDD：5.0V

　Data rate：128SPS

　FSR：±6.144V

　Mode：Continuous-Conversion Mode（operating)

 

 

We can find the Power dissipation 0.9mW Typical in the ADS1118 datasheet.

But this condition is Data Rate=8sps, FSR=+-2.048V.

On other E2E thread, I can find the following. I understand power dissipation of 12SPS is same as 8SPS.

>>The modulator frequency of the device doesn't operate any faster for different frequencies. The digital filter changes, but it does not require any extra power.

 

How about the FSR? Please advise me.

Thanks and best regards,

M.HATTORI.

  • 0
    TI__Guru* 97775 points

    Hattori-san,



    The power consumption and supply current should not change with the FSR setting.

    When the FSR/gain setting is implemented as an amplifier, as in some of our other delta-sigma ADCs, the supply current may increase. However, in the ADS1118, the FSR/gain setting is achieved through changing the size of the input sampling capacitor. This shouldn't change the current used by the device. The one big effect on changing the input sampling capacitor is that it will change the equivalent input impedance of the ADC, so the input current may be larger.

    The supply current will change most with the supply voltage on VDD, which you can see on Figure 32 of the datasheet on page 15.


    Joseph Wu