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CC2540: - ADC power consumption.

LzBone
Intellectual 770 points
Part Number: CC2540


Hi,

I am interested to find out about the my CC2540 ADC conversion power consumption.

First allow me to describe my set up.

(1) below is the code i use. P06 detect ADC input and measure with resolution 8. It will sample ADC value of P06 in an event every 1 sec.

(2) I measure with similar set up as described in AN09 power consumption measurement set up.

http://www.ti.com/lit/an/swra347a/swra347a.pdf

Put 10 ohm resistor in front and measure the voltage across that 10 ohm with oscilloscope.

Then measure duration and current level during an event and put those info inside the power consumption excel file as below:

www.ti.com/.../litabsmultiplefilelist.tsp

I get my results to be 35 micro Amp during that event that has ADC sampling.

My Questions are as follows:

(Q1) From following document from TI "http://www.ti.com/lit/ds/swrs084f/swrs084f.pdf"it shows that ADC consumption is significantly high than mine. So my method is measuring ADC consumption is not correct?

(Q2) If my measurement method is not correct, then can anyone kindly suggest the appropriate method for such measurement?

P.S The reason I want to verify is because, in my implementation, I am going to run some algorithm based on ADC value during that event. And I wants to find out the consumption of that whole event, which involve both ADC conversion/ ADC value detection + algorithm. In above code, i did not show that algorithm.

Regards,

LB

  • 0
    TI__Guru**** 317180 points
    The Excel sheet you are referring to calculate the average current with a given BLE connection interval. If my understanding is correct you want to measure the current when you are doing a ADC measurement. From what I can see from your measurements you are measuring 7.2 mA when doing a ADC conversion. It sounds a bit high, which other parts of the chip do you have on when you do this operation?
  • 0
    TI__Guru** 106705 points
    Hi LB,

    The datasheet number is not an average when running the ADC at a certain interval which is what you are measuring.

    You are measuring 7.2 mA which is quite close to the active mode current consumption (6.7 mA) + ADC (1.2 mA).

    Of course, from an application point of view, what you are doing makes sense as you want to know your average consumption.

    Cheers,
    Fredrik
  • 0 in reply to Fredrik K
    Intellectual 770 points
    Hi Fredrik K and TER,

    Thank you for quick reply. Now, i understand more clearly. Thanks a lot indeed :)

    Regards,
    LB