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Modeling >> Behavioral Models >> Input DC voltage varaiations of an OPAMP
https://designers-guide.org/forum/YaBB.pl?num=1133265008

Message started by packiaraj on Nov 29^th, 2005, 3:50am

Title: Input DC voltage varaiations of an OPAMP
Post by packiaraj on Nov 29^th, 2005, 3:50am

Hi,
I am trying to model the output voltage variations due to the varying input common mode DC voltage for an OPAMP (for DC simulations) in verilogA. As I understand, the OPAMP would work in desired manner in the range (Vin_CM_low to Vin_CM_High). Above or below this range the output would saturate.

I have problem in modeling the output for in-between range of input CM voltage i.e., between (Vin_CM_low to Vin_CM_High). If I can use a "sigmoid function" [1/(1+exp(-x))] as a solution for this, what parameter of the OPAMP controls the slope of the sigmoid funtion.

Thanks in advance,
Packiaraj.V.