[sdiy] LM394 vs. MAT02 vs. ?

[Ian Fritz]

At 04:18 PM 11/9/2004, Paul Perry wrote:

> > Better reasons for using expensive pairs is the improved log conformance
> > (low Rb) and noise.
>
>Is there a simple way to compensate for the Rb??
>
>paul perry Melbourne Australia

Well, yes there is. :-)

  In fact, there are several ways to do this.  If you look at just about 
any serious converter design, you will see something like an extra diode 
and feedback resistor.  Those form the Rb compensation. The trim is usually 
refered to as "HF tracking", or something similar.  My favorite variation 
is the one presented by Rene.  I can't ever remember where Rene keeps it, 
so here an example in one of my converters (R18 and Q3).

http://home.earthlink.net/~ijfritz/sy_cir9.htm

   Ian