I don't think there is any need for even moderately extensive model of OTAs. I've done some extensive analysis some time ago, only mirrors you should care about are output pair of mirrors, for their output impedance and because they could saturate in some topologies (OTA-C with high impedance unity gain buffer, instead of opamp based integrator, Roland and SEM in short), and even in those topologies OTA output is nowhere near rails in real life synths. So, OTA output resistance is more than enough IMHO.mystran wrote:As for LM13700 .. I actually plan on adding a "not so realistic" model of that, probably as the first integrated component. All the current mirrors in that thing can make a simple filter quite expensive in terms of CPU, so IMHO an "economy" version would make a whole lot of sense here.
On input side, bias currents, hfe vs Ic variation and bulk emiter resistnace of input pair has some influence, so I would go with 3 options: a) two npns on input, ideal mirrors, and output resistance, b) same as a) but two npns replaced with VCCS, linear hfe and c) ideal OTA with just tanh for nolinearity.
BTW, it would be really nice if you could include some utility compononents, for example varibale gain inverting on noninverting amp (linear, inf Zin, 0 Zout, gain can be changed between say 30d and -30dB, in the same way as resistance of resistors), also varibale gain instrumentation amp (diff in -> single end out) and variable gain differential driver (single end in -> diff out) would be great as well. I miss those more than pnp.