Hello All,

I would like to be able to use the available small signal AC analysis to evaluate any given OTS(Off the shelf) LDO for its major datasheet electrical characteristics such as ;

1. Output noise- VONOISE- nV/Hz^2
2. PSRR
3. Gain Band Width of the error amplifier
4. open Loop Gain

Would any of you experts out there be aware of such a once stop test method?I am kicking the tires here with a discrete LDO design based on a LinTech LT1490 opamp.This is to familiarise myself with the process of AC loop response analysis and is purely educational. I am injecting the AC signal in to the inverting pin of the Opamp instead of the traditional injection point on the Non-inverting pin through the AC coupling cap which is AC short,DC open. And I am looking at the VDIV as the one Femto Henry INductor is DC short,AC open and that ways,my belief is that  I still have the AC path for the  feedback loop  and I can affect the loop compensation by varying capacitor C5. But I notice that my Opamp is not biased properly any more. I have the schematics attached herewith. If you notice anything abnormal please let me know. It is needless to say this is my first attempt at SPICE modeling and any help in any form would be greatly appreciated!.

Thanks again,
AnalogNoob