the v2164 VCA has a gain coefficient of -3300 ppm/C. I'm not 100% sure how to use this figure. If i put a control voltage of -660mV (20dB) and an input voltage of 1 volt, how do i calculate the difference in gain per degree celsius?

 

the v2164 VCA has a gain coefficient of -3300 ppm/C. I'm not 100% sure how to use this figure. If i put a control voltage of -660mV (20dB) and an input voltage of 1 volt, how do i calculate the difference in gain per degree celsius?

The datasheet says there is a gain constant of -33mV/dB. The next line says the (typical) Gain Constant Temperature Coefficient is -3300 ppm/°C.

Therefore, for each 1°C rise in temperature, you can expect about a -3,300/1,000,000 change in the constant.

Note that this is typical! They don't give a min or max -- so use with caution.

 

They also supply a handy graph!



Though, I have no idea why they show +/- values on the temperature axis. I've never seen that before.

 

The THAT Corporation makes VCAs similar to the v2164 and they have several application notes that address your question:

What’s a PTAT Temp. Coefficient, & Where Does It Come From?
Dealing with the PTAT Coefficient

 

thanks! thats a great help