[sdiy] More OTA meas.

[Ian Fritz]

Hi Folks --

I had a chance to look at a couple more things today.

First I looked at another 13600 chip and verified the 9% nonlinearity for 
Iabc of .25 mA and .5 mA.  Then I tried the idea of tying the buffer input 
to the (-) rail to keep it from drawing bias current.  This had no effect 
whatsoever on the transconductance.

Finally I looked at the 3280 Iabc linearity.  Again, just considering .25 
mA and .5 mA the nonlinearity measures 1.5%.

So the 3280 and even the 3080 are clearly way superior to the 13600 (factor 
or 5) with respect to Iabc linearity.

   Ian