Differential ended to Singled ended [IMPORTANT]

[Tahar]

differential to single ended site:edaboard.com

Hi guys, this last couple of days I had the following headaches :


we Have a differential OTA.

and We have a nice 1.5 bit flash ADC circuit that works with an input range of [0,1V]


1) Some people of my groups said :


Is it possible to retrieve a simple single ended OTA from the fully differential OTA ?

so that we use conventional circuit and no headache for using this single ended input flash ADC.

2) The other group said : No we cant, we have to used a fully differential structure of All the circuits since fully differential OTA imply differential input and output for the whoel circuit that we are buuilding.

And in that case we have to think of to convert a differential ended input to a single anded input with a DC ofset of 0.5V. ok ! but how to do it ?

(no use of transformer or Balun here please)


Please help me !!!!

 

[willyboy19]

To get best performance, you should always resort to fully differential structure. For this case, even if you have single-ended input, you can always use a pseudo-differential input sample-and-hold stage to convert to the internal fully differential signals.

 

[yibinhsieh]

For CMOS process, the differential circuit can reject many substrate noise and I suggest you should always use fully differential circuit in your design. If your input a singled-end one, you can transfer it to differential in the first stage.

Yibin.