Does anyone know of a voltage regulator model?  Currently I'm using a non-ideal op-amp wired up as a unity-gain amplifier.  This actually works fine except that it takes around 1 us of sim time to reach steady state.  Perhaps my real goal is to have a realistic model (you see dips when charge is pulled) that can settle quickly.  I'm open to suggestions!

Thanks!

The schematic is an opamp driving a PMOS to source current through a two resistor string.  One terminal of the opamp is a reference voltage and the other is tied between the two resistors.  The regulator output is at the drain of the PMOS.

I'm not clear on how initialization statements could help.  The regulator output is initially at the desired value.  With a period switched-cap load, e.g. the regulator power an inverter switching high and low (charging and discharging a cap).  As soon as the first switching event happens the output of the regulator drops but does not recover.  Eventually the voltage does recover enough to reach a steady state with an average output voltage that is desired.