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    Current and degeneration resistor in input pair

    In analog audio amplifier, what is the calculation to do concerning the degenerative resistances of the differential input emitters?

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    As I understand it, the degeneration resistors R1 and R2 in the circuit, together with the Cdom (miller compensation) decide the cut-off frequency and therefore the total band of the amplifier.

    However, they also play an important role in response speed, or slew rate. For this parameter, the amount of constant current arriving at the differential is also important.

    How to optimally calculate R1, R2, Cdom and the differential current?

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    Re: Current and degeneration resistor in input pair

    Did you sketch the circuit right? As drawn, Cdom is no Miller capacitor. Q5 should be npn.



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    Re: Current and degeneration resistor in input pair

    Quote Originally Posted by FvM View Post
    Did you sketch the circuit right? As drawn, Cdom is no Miller capacitor. Q5 should be npn.
    Yes sorry, should be NPN, error of mine.



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  4. #4
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    Re: Current and degeneration resistor in input pair

    Degeneration Resistors improve the linearity,increase the Input Resistance that's all..
    There is no closed form equation for Calculation of Degeneration Resistors in Large Signal Mode.(there is just for small signal analysis)



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