CA3080 biasing

Discussion in 'General Electronics Chat' started by Neil Groves, Dec 19, 2011.

  1. Neil Groves

    Thread Starter Member

    Sep 14, 2011
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  2. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    the link doesn´t work
     
  3. Adjuster

    Well-Known Member

    Dec 26, 2010
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    I wondered about that when I saw it first, but I'm fairly sure the reason is to get the voltage required to control the CA3080 within the range available from the 3403 op-amp driving it.

    The amplifier bias control input is only one junction potential above its negative supply input, and the 3403 does not seem able to go down that far.

    http://www.intersil.com/data/fn/fn475.pdf

    http://www.ti.com/lit/ds/symlink/mc3403.pdf

    Edit: Kubeek is right: I had to refer to this to see your circuit http://experimentalistsanonymous.com/diy/Schematics/Full%20Synths%20Drum%20Synths%20and%20Misc%20Synth/Syntom.pdf
     
  4. Neil Groves

    Thread Starter Member

    Sep 14, 2011
    125
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    Last edited: Dec 19, 2011
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