hi,
   i have designed a  two stage op amp with 1v supply in 65nm tech.
   input common mode voltage=0.4 to 0.7
   output bias point =0.5(swings from .2 to .9 )
now i connected in  non inverting configuration  with gain 3 then it is saturating because of output swing limitation(actually op amp trying to go 1.2  because non inverting input i gave .4 as bias )  means op amp is trying to amplify both signal as well as bias. Is there any method to subtract bias voltage in the feed back  so that we can get wide range of gains
thanks

It sounds to me you are connecting the feedback resistors to DC GND rather than an AC ground whose DC bias point should be the same as the input common mode.
In this way you will not amplify the bias point and will take advantage of the output dynamic range.
This is the only way a non-inverting amplifier can work without amplifying the DC operating point. Otherwise you will have to use an inverting configuration

Regards
Tosei

Hi

In order to make it work without amplifying the bias circuit you have to separate the bias from the signal to be amplified. Otherwise you will amplify the DC bias input voltage. See the drawing for reference

Tosei