DC Blocking Capacitors - RF Cafe Forums
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Post subject: DC Blocking Capacitors Posted: Thu Jan 10, 2008 12:16 pm
Joined: Wed Aug 16, 2006 8:20 am
I am using a 1.5 to 8 GHz LNA for one of my applications. Un fortunately, I have to use off chip DC blocking Capacitors. How should I select the offchip Blocking CAP so that it provides very loww insertion loss and doesn't effects the noise figure much. This application works over 3.25 to 8 GHz
Design Engineer- RF
Post subject: Posted: Thu Jan 10, 2008 12:25 pm
Joined: Thu Sep 25, 2003 1:19 am
Check out the silicon caps from Vishay. I use them in a similar application. Performance is good, soldering them to the boards is a nightmare.
Post subject: Posted: Fri Jan 11, 2008 2:16 am
Joined: Mon Jun 27, 2005 2:02 pm
There are many manufacturers for RF capacitors: AVX, Murata, Taiyo-Yuden...
To get low insertion loss, I choose the value for the capacitor to give a reactance Xc of 3 to 4 ohms in the lowest frequency of operation.