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MSPM0G1106: using ADC, VREF

WorkerBee
Prodigy 100 points
Part Number: MSPM0G1106
Other Parts Discussed in Thread: LM4040

I am looking to use 8 of the ADC pins for measuring voltages.


1) in terms of accuracy it seems that an external reference helps a little bit.  I was wondering if you could quantify how much each of these could help and make a recommendation.

a) using an external reference, VREF+ only

b) using an external reference, using VREF+ and -

c) using an external reference of 3V instead of 2.5V

d) I do have the ability to generate an external 3.3V reference from 5V, different than the 3.3V VCC, but I wasn't sure if that was going to cause any troubles if the ref were above vcc, or how much it would help



2) If i'm using an external reference, can you advise?  i'm not in a power critical design.  I would like something that will not likely have supply issues.

the LM4040 seemed like a good starting point, but its an older part.  Should i be looking at a different family?  you have many LM, REF parts which can do the job.

thanks.

  • 0
    TI__Guru 56685 points

    Hello WorkerBee,

    The datasheet for the device will include ADC accuracy parameters for when you are utilizing both an external reference and the internal reference. I can't quantify by how much until the production silicon datasheet is released and those numbers are provided. In general though, you will get better accuracy results with an external reference. 

    You should never input a voltage to a pin beyond VCC +0.3V. Please see datasheet for more details, exact voltages and exceptions. 

    Your reference voltage input to the device will depend on the full scale range and resolution requirements for your signal being sampled. 

    For recommendation of an external reference, unfortunately I cannot give one as I'm not familiar with that portfolio. I would suggest making a different post in the voltage reference forum giving them key parameters and concerns in order to get a recommendation.