MOS Capacitor instance or a mosfet used as a cap (D-S-B connected to gnd)?

Hi, in Cadence Spectre simulations should I use a MOS cap instance or a mosfet (D-S-B connected to gnd) to simulate a real life MOS-cap? I tried both of them and they gave different results i.e....

27 December 2020 6,544 1 View