[sdiy] Speaking of OTAs....

[Grant Richter]

Thank you, this was very helpful.


> Harry is on the right track, but 10k / 51R is not the solution either.
> 
> 100k/510 *and* Id makes no sense.
> When Id is applied, the diodes take over the part of the shunt resistor
> (only that they are nonlinar to pre-distort the input voltage), so their
> resistance must be small compared to the outer resistors (to both of
> them!) If you look at the data sheet, something like 10k / 500
> is suggested with Id = 1mA. The diodes, in conjunction with the 10k
> resistor, will divide the input voltage down to the required millivolts.
> The 500R's to GND are just for biasing the diodes. If you make them
> too small, they will "bypass" the diodes -> less predistortion -> bad!
> The data sheet shows the bias resistors as "current sources" in a simplified
> diagram, and this gives an idea of what their purpose is.