[sdiy] Fairchild uA726

[Graham Atkins]

Hi David,

Some versions of the Minimoog VCO I believe. I bought 3 of them at an
auction several years ago (NOS). They are like gold dust and command
a high price which is probably why nobody uses them, like CEM and SSM
chips. I'm sure many others on the list can tell you more.

Graham

On 23 Sep 2009, at 18:50, David G. Dixon wrote:

> I was flipping through a fantastic (albeit very old: 1976) book I  
> found
> languishing in the stacks of the UBC library, the "Handbook of  
> Operational
> Amplifier Circuit Design" by Stout and Kaufman.  I was studying the
> schematic for "a differential-input logarithmic amplifier with  
> adjustable
> gain and logarithm base" in Fig. 17.1 on page 17-2, when I came upon  
> this
> passage:
>
> "Several other design tricks will keep this circuit from drifting with
> temperature.  Transistors Q1 and Q2 should be a matched pair of  
> devices on
> one chip.  Ideally they should be gain-regulated such as the uA726
> temperature-controlled differential pair (Fairchild).  This device has
> active temperature-regulating circuitry on the same chip as the  
> matched pair
> so that external temperature sources have no effect on transistor
> parameters."
>
> This sounds like the ideal device for building expo converters.   
> However, I
> could find no reference to it on Google, and no datasheet in the
> datasheetcatalog.com database.  Does anyone here know of this chip?   
> Is
> anything similar still being manufactured?  Did any vintage synths  
> use it?
>
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