[sdiy] Spice/mathematical model of SSI2164

[Neil Johnson]

Hi Liam,

> This is the crux of why I wanted to understand this more (rather than just build the datasheet design). I'd like to use this for a triangle-core oscillator. The obvious (I think) way to do it would be a have the sign of the input current into VCA2 alternating and feed the output straight to the integrator.

That could be a problem as you would lose the benefit of the
performance of the NPN transistors in VCA2 during the positive half
cycle.  It would be better to treat this as a black box with a
negative current coming out of it - for example it could easily drive
a sawtooth oscillator.  Or feed that into an op-amp I-to-V inverter
and then into the classic triangle VCO.

Neil