What's the meaning of CAP parameters (Cdd,Css,Cgg etc.)?

[spring1860]

hi
after a simulation in spectre, print the DC Operational Points ,we see parameter CAP. such as Cdd,Css,Cgg and gmoverid, type.....

can anybody tell me what's the means of all above stand for

thx.

 

[spring1860]

Re: about Cdd

nobody use spectre?

 

[abcyin]

about Cdd

Hi,
these capacitor demonstrate the capacitance looking from a given terminal, for example, the Cgg is equal to Cgs+Cgd+Cgb, in the print results display window, you can find this correct.

hope it helps!

 

[spring1860]

Re: about Cdd

Hi,
these capacitor demonstrate the capacitance looking from a given terminal, for example, the Cgg is equal to Cgs+Cgd+Cgb, in the print results display window, you can find this correct.

hope it helps!

yes, u are right , but what confuse me is why capacitors are negative , e.g. cgs=-236.6f

 

[abcyin]

about Cdd

Hi,
I did not get a negative value for these capacitors, maybe the polarity is taken into account in your design kit, or you'd better check the transistor that whether it was in the right working state.

Hope it helps!