ODP: VCA chips

[Roman Sowa]

1. That's what balanced pairs are made for - two (or more)
transistors in one piece of sillicon are at (almost) the same
temperature no matter what. That's why they stay
balanced with temperature changes...
But balanced transistor isn't enough for precise exp converter.
Exponential argument of Ube to Ic equation changes with temperature,
and that affects everything.

2. Don't they have it at Harris?
http://www.harris.com

Roman

	Paul Perry wrote>  

> 2 questions left:
> 
> What do you think about high control currents for discrete transistor
> pairs
> ?
> Any drawbacks ? Do the transistor pairs unbalance themselves due to
> self
> heating at higher currents ?
> 
> Availabillity of the CA3280 - I know it's hard to get in Germany. But
> is it
> still manufactured or not ? I have a few left, but I hesitate to use
> them
> if
> I can't get them in the future ...
> 
> JH.