Comparator in Analog To Digital Convertor

Thread Starter

Majid Vatan Parast

Joined Dec 6, 2014
5
Hello everybody
I want to design a charge redistribution SAR ADC , but my comparator does not work for negative input , it does not compare zero and negative voltages correctly , I have got the comparator circuit from a paper . what should I do?
Please help me :(:(:(
 

Tako

Joined Oct 21, 2014
51
Thanks for the information.

Your comparator is not able to compare 0V with negative voltages. You have NMOS transistors as input transistors. For example when:

INP = 0V
INN = -1V

both transistors are off. You need PMOS as input transistors.
 
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