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Double gate Mosfets

Discussion in 'Electronic Design' started by [email protected], Nov 14, 2008.

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  1. Guest

    Hi all!

    I need to build an ultra low noise cascode amplifier and I want to use
    a double gate mosfet to gain better performances with respect to
    jfets.
    I need a very low gate leakage current, because it worsens the SNR.

    I found some interesting components made for RF purposes by NXP, but
    all have protection diodes and also a bias network integrated in the
    package.
    I need to find a mosfet with naked gates. I know they're very
    sensitive to ESDs, but I need very low leakage and I can't tolerate
    the leakage of the protection diodes.

    Can someone help me?
    Thanks!
    Marco
     
  2. MooseFET

    MooseFET Guest

    Try Calogic. They make small signal MOSFETs without protection
    diodes.
     
  3. Guest

    Hi John,
    thanks for replying.
    Ok, the mosfet has to be used in a charge sensitive preamplifier
    configuration. At the present moment I'm using a jfet before an op-amp
    with a drain resistance of 1Kohm, but I want to try a double gate
    mosfet to be able to remove the drain resistance which increases the
    drain current noise.
    If I use a double gate mosfet, I can obtain the desired drain current
    by biasing the first gate and applying the signal to the second one.
    The problem is that I need very low gate leakage current (to reduce
    noise), so the need for a mosfet without gate protection diodes.

    This is all. I hope I've clarified the problem
    Thanks all :)
    MArco
     
  4. Guest

    Thanks for the advice,

    unfortunately they don't make double gate mosfets. I only found
    devices with the external bulk connection but the transconductance was
    too low.
    Thanks anyway :)
    MArco
     
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