Hello LTspice!
I was addressing an issue with one of the active learning exercises:
https://wiki.analog.com/university/courses/electronics/electronics-lab-heartbeat
The AC analysis ran just fine, but I was double-checking transient and it would hang at ~1.5 microseconds. Strange. On a hunch, I took out the last two op-amps (leaving only a single OP284) and the the transient simulation ran fine.
On another hunch I replaced all of the OP284s with LT6015s - also worked fine. Just to triple check, I built up the circuit below, alternately swapping in LT6015s. Sure enough, it will run if there's one LT6015 and one OP284, but NOT if there are two OP284s. Screenshot pasted below - I see spikes to +50V, -170V...
Could this be a bug in the OP284 model?
Thanks!
-Mark
Test circuit with one OP284, one LT6015:
Circuit with two OP284s:
