Double gate Mosfets

Nov 14, 2008 4 Replies
M

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


Vote
Twitter Facebook LinkedIn
J

What frequency? What bandwidth?

John

Vote
Twitter Facebook LinkedIn
M

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

Vote
Twitter Facebook LinkedIn
M

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

Vote
Twitter Facebook LinkedIn
M

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

Vote
Twitter Facebook LinkedIn

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required