Datasheet: Output capacitance at Static(DC) vs Dynamic(AC) ? diff

[faizalism]

Hi,

I am referring to 1 of the datasheet and found that they stated different output capacitance at Static and Dynamic characteristic.
ie.

Static, Co output capacitance , min = -, max =7pF

Dynamic, all output load = 25pF

Why there is different for that capacitance setting? Any specific reason.

Thanks,

 

[artmalik]

Static and Dynamic capacitances are terms used with respect to frequency of operation of the design. Static means the cap offered by the design with the low frequency while at higher frequencies it is 1/jwc so there are two numbers. Also static will also mean there is no activity so it will amount to the total metal cap offered while in dynamic it includes the Cgs,cgd etc of the driver along with the metal cap.