What define Cgb Cdb in hspice simulation? Help!

[xiexi]

The Cgb and Cdb is defined by layout diffusion size which is AD, PD, AS, PS. But I am confused that when I simulate using level 49 model the Cgb and Cdb exist without writing AD, PD, AS, PS parameter. I wonder how to defind these parameters in hspice program if I don't write them. Thanks!

 

[castrader]

i think cgd cdb cgs is include in the models not in the spice file.
you can use lx18 - lx34 see it (details in hspice mannual)

 

[farrokhiyan]

Hi dear friend
You can specify device characteristics for default values. you can see more information in hspice manual. the default values are determined in technology file.

See this picture :



Regards

 

[pfd001]

The Cgb and Cdb is defined by layout diffusion size which is AD, PD, AS, PS. But I am confused that when I simulate using level 49 model the Cgb and Cdb exist without writing AD, PD, AS, PS parameter. I wonder how to defind these parameters in hspice program if I don't write them. Thanks!

If you dont define AD,PD,AS,PS, spice will use the default settting. They can be calculated by the W, L