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TMS320F28075: About F28075's ADCIN14 pin

Sh.Sasaki
Guru 13625 points

Part Number: TMS320F28075

Hi,

Is there a reference circuit or reference program for following yellow comment?

SPRS902D: p.10

Best regards,

Sasaki

  • 0
    TI__Genius 15955 points
    Hi Sasaki,

    Thank you for your post. Your thread has been assigned to a C2000 expert and should be answered soon.

    Best regards,
    Chen
  • 0 in reply to Chen Jiang ti
    TI__Guru 60865 points
    Hi Sasaki,

    Basically you would want to get an external high-accuracy voltage source that is towards the upper part of the ADC range (maybe 2.0V if using a 2.5V VREFHI or 2.5V if using 3.0V VREFHI). You then apply that to all 4 ADCs via the common pin and use the sampled reference voltage to calibrate out any gain error or ADC-to-ADC gain error.

    We don't expect this to provide a significant improvement vs. the datasheet specifications and wouldn't recommend this for a typical application. This would only be if you are really trying to squeeze every bit of accuracy out of the ADC.

    Also see: e2e.ti.com/.../2010854
  • 0 in reply to Devin Cottier
    Guru 13625 points
    Hi Devin-san,

    Thank you for your support.
    I understood it.
    I will use the calibration method described in TRM.

    Best regards,
    Sasaki
  • 0 in reply to Sh.Sasaki
    TI__Guru 60865 points

    Hi Sasaki-san,

    To be clear, if you want to meet the datasheet specifications, you don't need to do any self-calibration of offset, gain, or ADC-to-ADC gain.  As long as you use the SetMode() function to setup the ADC, the correct linearity and offset trims will be loaded.  All other trims are loaded on power-up via the boot-ROM.  

    Only if you want to squeeze more accuracy out of the device would you do self-calibration, as described in the linked e2e thread.  I think the TRM also describes how to self-calibrate the offset error, but this isn't necessary on this device; the factory offset trim should be good. 

  • 0 in reply to Devin Cottier
    Guru 13625 points

    Hi Devin-san, 

    Thank you for your detail information!!!

    I really appreciate you!!

    Best regards,

    Sasaki