Dual-Gate MOSFET - RF Cafe Forums

RF Cafe Forums closed its virtual doors in late 2012 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2012, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts. Here is the full original RF Cafe Forums on Archive.org

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layla

Post subject: Dual-Gate MOSFET Posted: Sat Nov 11, 2006 9:32 am

Captain

Joined: Thu Aug 10, 2006 7:09 pm

Posts: 7

Hello everyone. I was wondering if you can help me set up a simple circuit to utilize the BF988 dual-gate MOSFET as a switch to pass on (or prevent the passing of) a 315MHz sine signal. I was thinking of inputting the 315 MHz signal into one gate and the control (ON/OFF) signal into the other gate. Would that work. Your advice and suggestions would be greatly appreciated. Thanks.

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IR

Post subject: Posted: Sun Nov 12, 2006 4:42 am

Site Admin

Joined: Mon Jun 27, 2005 2:02 pm

Posts: 373

Location: Germany

Hello,

This looks like a good idea.

You should assure that the level of the control signal is much higher than the 315MHz RF signal. Looking at the curve of Gain vs Vgs1 voltage in page 5 of the data sheet, shows how much the signal would be amplified or attenuated. The gain response over the Vgs1 voltage variation looks flat with some peaks.

I would however also consider another circuit: Why not using an RF switch?

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Best regards,

- IR

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melkhouly

Post subject: Posted: Thu May 03, 2007 5:17 am

Captain

Joined: Thu May 03, 2007 2:55 am

Posts: 8

Location: Egypt

yeah RF switch will give good performance ,

also check NXP they produce some MOSFETS and Switches for RF

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Khouly

Posted  11/12/2012