gEDA-user: TL431

[gene glick <carzrgr8@xxxxxxxxxxxxx>]

Anyone use these shunt regulators?  I'm wondering about the max voltage. 
 Data sheet says max cathode-to-anode voltage is 36V.  What if VCC = 50
V, as in this cheezy drawing is trying to show.  R1 and R2 set the 
output voltage at the emitter.  R3 limits the current to the cathode 
*and* drops enough voltage (greater than 14V) to allow the the 
cathode-anode voltage to be within 36V.  Is that legit?  Or maybe I have 
to design in some circuitry to drop the voltage down at the cathode.

             (npn)

VCC ------ C       E ------
      |      \   /        |
      /      -----        /
  R3  \        | B        \
      /        |          /   R1
      |        |          \
       --------|          /
               |          |
               |          |
            ------/       |
           /  / \         |
   TL431     /   \---------
             -----        |
               |          /
               |          \  R2
               |          /
               |          |
               |          |
               ------------
               |
            --------
           /   /   /


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