25W DC-DC Buck Converter

This is an interesting control scheme. It looks like your turning on the PMOS when the inductor current falls below the level set by the error amplifier. Is that right?

Yes, when the freewheel current signal drops below the error voltage signal the PMOS is turned on, re-energizing the inductor. Have you taken one of your every circuit buck converters and simulated it in LtSpice? I cannot get the error voltage amp to behave, hence why I started experimenting with the OTA.

Yes, I have simulated dc dc converters in LTspice. They have worked. Do you compensate the op amps correctly?

I believe so. I've been following guides, the best one, in my opinion, being this one: https://www.ti.com/lit/an/slva662/slva662.pdf I've encountered mixed results. I'm of the opinion that there's some poles/zeros associated with the op amps I've been choosing in LtSpice... or something more strange going on? I don't have a lot of experience with AC only feedback with a mixed AC/DC input signal LtSpice, so I'm not sure if what I'm looking at is normal or not? What's weird is the overall shape of the frequency response tends to look the same from op amp, to op amp, to op amp, regardless of the amp I choose (with the exception a few, but the response is'nt what I'm looking for). The frequency response in EC tracks closely to what I'd expect, according the documents I've been reading. Which Type of Compensator do you favor? OTA, or op amp? Do you use any calculators i.e. the analog devices calculator?

The low component values in this circuit to me, at least intuitively, don't seem right. But the frequency response looks exactly as I anticipated it would: https://everycircuit.com/circuit/5200667167424512/type-iii-compensator Trying different binding frequencies, about a decade apart, and thus different component values, values that make more sense, LtSpice still produces the same overall frequency response shape. Something isn't right. Maybe I need to simulate an ideal op amp in LtSpice but then, what's the point?

Here's a type II I put together as well: https://everycircuit.com/circuit/6660603256766464