large signal halfwave rectifier

[mwlab]

Hello,

I am designing a half wave rectifier for a large signal case. The design environment used is ADS. I am using the SPICE model mentioned in the datasheet of SMS 7630 (Schottky diode). What I am not sure is whether this model is for a

(i) small signal nonlinear model
(ii) large signal nonlinear model

Looking forward to replies.

Thank you.

 

[BigBoss]

Of course Large Signal Model should be used.
There is no such thing "Small Signal Nonlinear Model". All small signal models are linear.

 

[mwlab]

Of course Large Signal Model should be used.
There is no such thing "Small Signal Nonlinear Model". All small signal models are linear.

I=Isat*(exp(qV/kT)-1) is nonlinear but isn't this applicable only for small Signal analysis?

 

[BigBoss]

I=Isat*(exp(qV/kT)-1) is nonlinear but isn't this applicable only for small Signal analysis?

This is not a model equation, it's only Diode Current expression.
That may be used for small and large signals both. If "V" is assumed being as "varies around an operating point with small deviation", it can be used as a small signal expression with first term ( linear one ) or it can be used with large deviation around an operating point with higher degree series expansion terms, it's said that " a large signal equation" etc. So it depends only which region you attempt to use in.

 

[FvM]

Diode SPICE models work for small signal (AC) and large signal (transient, HB, PSS etc.) analysis. But they don't necessarily model package parasitics relevant for RF circuits.