[volt-nuts] Making a Reference IC

[Jack Mcmullen]

 Just thinking why would you reinvent a transistor/zener reference when the industry's voltage reference chips are in the $2.00 or less single quanities with performance far exceeding anything previously available in discrete components??




-----Original Message-----
From: Dave M <dgminala at mediacombb.net>
To: FEBO Volt-Nuts <volt-nuts at febo.com>
Sent: Sat, Sep 12, 2015 1:58 pm
Subject: [volt-nuts] Making a Reference IC

 
 
 
I was looking at the schematics for the Fluke 731 and 732 voltage  
references.  these, and several other brands and models of voltage  
references, use the same or similar reference ICs as their basis.  The  
reference ICs are a Zener/NPN transistor pair on a single substrate. 
 
Please view in a fixed-width font such 
as Courier. 
 
        | 
        | 
      C | 
        | 
          | 
          | 
           |---- 
           |  B 
          /| 
         / | 
      E | 
        | 
        +--------------- 
        | 
     /------/ 
       /   
      ------ 
        | 
        | 
 
Just thinking... would it be possible to make a reference with similar  
characteristics with discrete components (a low tempco Zener and a  
transistor)?  They would likely have to be closely coupled thermally and  
maintained at a constant temperature within an oven or by a peltier device. 
 
What criteria would apply to the selection of the parts? 
 
Dave M  
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