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TMS320F28377D: Driving ADC using single ended Op-Amp in 16bit differential mode

Barend Ungrodt
Intellectual 1420 points

Part Number: TMS320F28377D

Hi C2000 group,

I'm working with a customer who has some questions about the ADC converters in the TMS320F2837x:

  • Is it possible to drive these ADC’s using single ended Op-Amps in their 16bit differential mode? If yes, how?

  • Would it be possible to feed the 1.5V-shifted current-sense signal from the Op-Amp to the positive input and the 1.5V reference to the negative input?

Thanks so much in advance!

Regards,

Barend

  • 0
    TI__Guru 60865 points
    Hi Barend,

    (1) Yeah, you can use either 2 single-ended op-amps or one differential output op-amp for driving the 16-bit differential ADC inputs. Topology is going to depend on what the format of your input signal is. The best place for help with this is going to be the precision op-amp forums.

    (2) No, this won't work. The inputs are fully differential, not pseudo differential; the common mode of positive and negative signals needs to be near VREFHI/2, which won't be accomplished by tying the negative input to a static value.

    Also see some of these recent threads:
    e2e.ti.com/.../648919
    e2e.ti.com/.../650805