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  1. #1
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    How to choose JFET for front end amplifier

    I am designing audio amplifiers, I am not familiar with JFETs, how do I choose between J112 and J113

    https://www.digikey.com/products/en/...=1&pageSize=25

    My original design using BJT is running 1.2mA collector current, which one will fit better?

    Also if you get the datasheet of J111, from Fig.5 in the data sheet on input capacitance is lower the more negative the Vgs, meaning choosing J111 is better than J112 as Idss is higher with J111. Is that true?

    Thanks

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  2. #2
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    Re: How to choose JFET for front end amplifier

    Hi,

    I couldn't answer your question, sorry. An observation is that maybe audio needs switching jfets, 111/112 are for switching; types such as 5457 are signal jfets more bjt- like perhaps. There are app notes explaining this, related to jfet use based on process, e.g. process 55, etc.



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