[sdiy] AS3280 test

Ian Fritz ijfritz at comcast.net
Sat Nov 10 23:17:49 CET 2018

Hello --

Good news! Alex sent me a couple of his AS3280 chips, and they work great!

I didn't do extensive testing, just a couple of measurements in my usual 
test configuration, which is a standard VCA circuit. I benchmarked them 
against a CA3280 that had previously been selected for high performance, 
and against typical results for older devices.

Configuration: The input diode pins are fed a 1 mA current. The input to 
the control pin is 0 - 0.5 mA, and the output current is the same. The 
I-V converter output is 0 - 2V.

With the offset nulled at full gain, the variation in output voltage 
with Iabc is under 1 mV. My standard for a very good device is under 2 mV.

Output linearity vs Iabc was better than 1%, with two devices near 0.1% 
Devices I tested previously were mostly around 2%. So it shouldn't be 
too hard to select devices for critical multiplier applications.

Thank you Alex!



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