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TM4C123GH6PM: ADC ch-to-ch crossover

HS FAE Germany
Mastermind 32550 points

Part Number: TM4C123GH6PM

Hello,
is there any influence ADC ch-to-ch measurement? Eg. customer want to measure DC 3V on AIN8. The result fluctuate dependant on the voltage level of ACIN7. The sample time of 250ns should be ok.

Device: TM4C123GH6PM

Regards, Holger

  • 0
    Guru 117855 points

    Such, "Channel to channel" cross-over HAS been noted - both w/in this vendor's MCUs - as well as competitive ones.

    Best means to overcome appears to be, "Proper mating/provisioning of the Analog Signal's Source to the ADC's "prescribed/specified" input specification!

    (this usually means that the "signal source" must provide adequate drive current to meet the demands of the MCU's ADC input circuitry (especially input cap...)      Note that "back to back" channel conversion "sequence timing" may prove your "friend (when increased) or enemy" - and that each/every case proves unique...

  • 0
    Guru 27665 points
    There is good reference material in your own companies seminars. See #bookshelf for some references to the literature from these seminars.

    Also keep in mind that most of these devices do not have an absolute reference so their result also varies with the power supply.

    Robert
  • 0 in reply to Robert Adsett
    Guru 117855 points
    Is it not "poetic" that (even) vendor agents "share" our difficulty in "discovering the wealth of tech data" ... (so often "NOT in direct nor clear view!")