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using the 16 bit adc on delfino mcu

MARK PESACH
Intellectual 850 points

HI!

i want to use the DELFINO ADC in 16bit mode. 

in the manual it says that its only possible with differential mode,

but if my signal is referenced to ground i am still needed to use 2 adc inputs?

cant i use 1 input only - like in the single ended 12bit mode?

as i understand from the manual even if my signal is referenced to zero i still need use the negative input and 

connect it to zero .

also correct me if i am wrong , the only hardware difference between 12/16 bit is the value of the added capacitor  to the reference voltage?

thanks for your help!

best regards

Mark

  • 0
    TI__Guru 60865 points
    Hi Mark,

    You must use differential mode for 16-bit operation. Connecting the negative differential input to ground will not result in correct operation; you must actually supply a differential input and that input must meet the common mode voltage requirements as specified in the datasheet.

    If your raw input signal is not differential, you can buffer it through a fully differential op-amp, or use a pair of single-ended op-amps to generate the positive and negative halves of the input.
  • 0 in reply to Devin Cottier
    Intellectual 850 points

    Hi Devin

    thank you for your reply.
    i am planning to use single ended to differential converter (with 2 op amp).
    just wanted to ensure - the differential voltage input to the delfino 16 bit adc can have negative values ( ADCINxP - ADCINxN < 0) , but both pins(ADCINxP and ADCINxN) have to swing from 0 to VREFHI , and meet the common mode voltage requirements (VREFHI/2) ?

  • 0 in reply to MARK PESACH
    TI__Guru 60865 points
    Hi Mark,

    Yeah, that is correct. The pin voltages on both pins should be in the range of 0 to VREFHI and the average of the two pin voltages (the Vcm) should be within 50mV of VREFHI / 2.