AnsweredAssumed Answered

AD9625 Front End - DC/Single Ended vs. AC/Differential

Question asked by MalcolmC on Dec 22, 2015
Latest reply on Dec 7, 2016 by hoo

I'm using the AD9625-2.5-EBZ as my reference design which is set up for AC coupling and a differential input (single ended transformed by a balun).

 

My end application involves capturing pulses that are not periodic and occur relatively infrequently.  I also need to take advantage of the full voltage range of the ADC as my input signal can swing from 0V to +1V.  Pulse are in the tens of nanoseconds in length with rise times in the single nanoseconds.

 

Given the above criteria, it would seem that DC coupling a single ended input is the best path.  The AD9625 data sheet indicates that this can be done by tying the negative differential input to Vcm.  Is this a reasonable path to pursue?  Is there an app note that discusses DC coupling to this ADC in more detail?

 

Would it also be beneficial to put an op-amp between the input and the ADC?

Outcomes