I'm looking for something that can operate at +/- 2.5 volts. So far I have only located the THAT 4315 analog engine, which is fine, although it has RMS detection circuitry that I don't need. THAT 2150, 2180 etc single VCAs are nice but lowest supply voltage is +/- 4 volts. Exponential voltage control is ideal.
Um, why?
Well, aren't you the curious one.
I'm looking into making a tremolo that uses an exponential VCA controlled by a microprocessor that would run off 9V. I'd just as soon run any analog supply voltages through one regulation stage, so I'd rather not run something directly off unfiltered 9V.
LM3080 will run on hardly any voltage. LM37000 needs another part-Volt.
Not an "exponential VCA", but trem does not need a 60dB range, and your PIC can look-up an exp function.
Yeah, I was going to suggest LM13700 too. The SSM2164/V2164 would be good because of the expo control, but it requires the same +/-4V minimum supply.
I think it's based on the same core as the THAT Corp stuff.
The Alfa AS3360 (recent CEM3360 clone) claims to be able to run down to +/-3V, but I've never tried it that low.
http://www.alfarzpp.lv/eng/sc/AS3360.pdf
(Full disclosure - I buy plenty of chips from Alfa and have them in my shop.)
Tom
What about using one pwm output of the mcu to drive a switch as a variable resistor?