• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 82 subscribers
  • Views 464 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMS320F28069: TMS320F28069: ADC

jun zhang4
Prodigy 30 points
Part Number: TMS320F28069
Other Parts Discussed in Thread: C2000WARE

Hi Sir：

I sample a sine signal using an ADC of TMS320F28069. But I find that Vin=1.2 ADC Value =1.2     Vin=1.21 ADC Value =1.21  Vin=1.22 ADC Value =1.22  but Vin=1.25 ADC Value =1.27  Vin=1.27 ADC Value =1.27.

It just like the internal error comparator or op amp of ADC is broken.

  • 0
    TI__Guru 62975 points

    jun zhang4,

    There is no embedded signal buffering stage (such as an op-amp) for the ADC inputs in the device so this will need to be handled externally.

    Are you using a custom board or a TI evaluation platform?  Are you using TI example software for your testing?

    Can you describe the parameters of your sine input?  It is difficult to understand the significance of the readings that you have shared other than that there appears to be ~20mV of error when Vin=1.25V.

    -Tommy

  • 0 in reply to tlee
    Prodigy 30 points

    Hi  Tommy:

    I use the PCB，We layout。 the value I share it means  There is a fixed clamp value inside the ADC

  • 0 in reply to jun zhang4
    TI__Guru 62975 points

    jun zhang4,

    I think we would need more evidence to conclude that the ADC is malfunctioning. Do you have additional observations?

    Are you using the TI example software from C2000Ware? Do you have a TI EVM that you can use for comparison?

    -Tommy