[sdiy] 2164 temperature compensation

[Benjamin Tremblay]

Since I am cheap and impatient, I have used both the AS2164 and the AS3360 controlled by an inverting op amp driven by a pwm signal. Adding just a smidge of negative voltage gives you impressive dynamic range. 

Benjamin Tremblay

> On Aug 2, 2026, at 10:24 AM, Benjamin Tremblay <btremblay at me.com> wrote:
> 
> Replying to this so I can monitor responses, because I am curious. I noticed that the 2164 could operate at low supply voltage. But i interpreted the specs to mean you need at least a trickle of negative voltage to get the correct range out of this device. Maybe in this circuit where it’s not being used as a vca it’s okay?
> 
> Benjamin Tremblay
> 
>>> On Aug 2, 2026, at 9:35 AM, Rutger Vlek via Synth-diy <synth-diy at synth-diy.org> wrote:
>>> 
>> 
>> Dear list,
>> 
>> I'm working on a sawtooth oscillator for a new personal synth project and have a question about temperature compensation with the 2164, as proposed in the datasheet (Figure 11): 
>> https://www.soundsemiconductor.com/downloads/ssi2164datasheet.pdf
>> 
>> I noticed that the proposed compensation scheme takes a bipolar CV input (-5 to +5V) and generates a temperature compensated control signal for the final exponentiator (VCA2) that is also bipolar in nature, centered around the unity-gain point (0V) of the 2164. I wondered: was this chosen for practical reasons, or does the temperature compensation (or expo conversion) work more accurately around the center-point of the 2164?
>> 
>> The reason I ask is because I'd like to adapt this scheme to work with a unipolar CV coming from a MCU. I'm also wondering if I can drop VCA3, as high frequency compensation of non-temperature dependent effects can be entirely done inside the MCU.
>> 
>> Best,
>> 
>> Rutger
>> 
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