linear input current range simulation?

[patriot]

when simulating the linear input current range,i use "AC" analysis in spectre, however,the gain is sheerly linear no matter how much the input current is. and the output voltage can even be up to several volts and exceeds the supply voltage.
what is the matter?

 

[FvM]

I don't know the particular Spectre AC operation, but generally AC analysis is done by linearizing the circuit at it's bias point. Thus you can easily get kV or MV voltage. DC sweep or transient analysis would give the correct answer.