• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 46 subscribers
  • Views 620 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.

ADS4249 ADC Input Driving circuit

HendrikB
Prodigy 10 points
Other Parts Discussed in Thread: ADS42LB49

Hi

We are using the ADS42LB49 ADC in a design based off of the  ADS42xx EVM reference design. For the ADC Input driving circuit, what is the function of the centre tapped transformers?

We have ordered the WBC1-1L standard transformer without the centre-tapped windings, instead of the WBC1-1TL used in the reference design, which has a centre tapped secondary side. What would the effects of using this WBC1-1L transformer without the centre-tappped windings in the design be? Would the circuit still function correctly? 

Regards

Hendrik

  • 0
    TI__Guru* 91947 points

    Hendrik,

    The affects you probably will see is less filtering of ripple on the common mode level of the signal due to any possible amplitude mismatch or phase mismatch out of the transformer.  Amplitude or phase mismatch of the differential signal shows up as a ripple on the common mode level, and the AC cap to ground at the center tap gives a path to ground for the ripple, which is also the same reason we will split the termination resistor into two resistors with an AC cap to ground at the midpoint of the termination.  I am not sure by how much you would see the effects of the filtering though. You may want to experiment with the ADS42LB49 EVM and swap out the transformers or remove the cap to GND connections on the center taps to see what effect this has with your setup before deciding on going this route.

    Regards,

    Jim