[help]how to simulate input and output resistance in spectre

[skyeaglemm]

hello everyone ,i am a beginner to ic design, i dont know how to simulate input and output resistance in spectre ,can anyone help me, thanks!

 

[suvendu]

Re: [help]how to simulate input and output resistance in spe

i donot understand what is "spectre".please make it clear.there r many simulators r available. u can easily download them.from help menu u can understand how to use them.

 

[skyeaglemm]

Re: [help]how to simulate input and output resistance in spe

dear suvendu
i mean no matter what circuit simulator we use, either pspice ro hspice, how we usually simulate the input and output resistance of a circuit? for example ,a simplest one-stage common-source amplifier?

 

[Karthikeya]

Re: [help]how to simulate input and output resistance in spe

practically i do it this way
set ac input to a reasonable value in series with a pot (say 1MΩ) ->initially set pot=0 ->observe o/p->vary pot until the o/p reduces to half->this value gives the i/p resis
For MOSFETs the i/p resis is infinite ->no reason to use this method

o/p resis->set pot in parallel with o/p for fixed input voltage ->pot value=max->observe o/p value->vary pot until o/p reduces to half->pot value gives the o/p resis
this can be proved from the max power transfer theorem

though i havent tried it in simulator ...i think it shud work