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MSPM0L1105: Current consumption estimation

Tamas Kovago
Expert 3440 points

Part Number: MSPM0L1105
Other Parts Discussed in Thread: ENERGYTRACE,

Hi Champs,

Customer would need a current consumption estimation for the following use case:

MCU: MSPM0L1105TDGS20R

  • 3V supply
  • internal OPAMP is used
  • 6 external ADC channels sampled ~10kHz each, result transfered to RAM (DMA could be used), internal Vref 2.5V
  • 20ms timer interrupt with 1000 cycles software routine executed

Can you please help estimate?

Thanks and regards,

Tamas

  • +1
    TI__Genius 10060 points

    Hi Tamas,

    It will be hard to estimate, but I'll do my best. First, please note that the MSPM0L11x series doesn't have an OPA, but the MSPM0L13xx does. I'll assume the customer is using L13xx.

    1. Iq of the internal OPA is between 75uA and 400uA depending on the configuration. This is per OPA.
    2. The datasheet specs 300uA for 200ksps using VREF=2.5V. This is a faster sample rate, but we can say the upper limit is 300uA.
    3. This application is very lightly duty cycled (1000cycles at 32MHz every 20ms is <%1 duty cycled). Let's assume 1% as the worst case
      1. Idd_run = 3mA @ 32Mhz
      2. Idd_stop1 = 300uA worst case
      3. Average current assuming %1 duty cycle = 320uA

    If you add these up you get a worst case of around 1mA. Obviously, you will need to create a test case to validate this. You can use energytrace to help with that. This is a pessimistic example that assumes the worst case, I expect we could be under 1mA.

    What is your customers power budget?

    Regards,

    Evan

  • 0 in reply to Evan Lew
    TI__Expert 3440 points

    Hi Evan,

    Thanks for your feedback.

    The application is a DIN rail fuse monitor. It is allowed to draw max 2mA from a 100VAC line including power + MCU + latch relay + 2xLED. I think with 1mA@3V we should be good to go.

    Typo: internal GPAMP is good enough no need for OPA so MSPM0L1105 should be good enough.

    Many thanks and best regards,

    Tamas

  • 0 in reply to Tamas Kovago
    TI__Genius 10060 points

    Ok great, sounds good.

    If it is 2mA @ 100VAC then that should be plenty. 

    Regards,

    Evan