Here is a summary I once compiled for lecture notes regarding SPICE integration methods: • TRAP and GEAR are the most heavily used integration methods in circuit simulation. • For a fixed time-step ∆T, the most accurate method is TRAP, followed by GEAR. • TRAP is overly sensitive to errors of previous time steps, so not to be used when RELTOL is loose! • For abrupt signal changes, BE (backward Euler = GEAR order 1) and TRAP adapt fast, so they can provide an advantage, but one needs to be aware of the ringing introduced by TRAP. • GEAR2 is efficient for simulating with tight tolerances or smooth waveforms. • BE, TRAP, and GEAR2 are stable on stiff circuits (i.e. don’t show ringing) but BE shows strong artificial numerical damping (TRAP shows no damping, GEAR2 weak damping). • Overall, GEAR2 seems to be preferred by most circuit designers. Set the GEARx order by

.options *MAXORD=x*