Post subject: DC Blocking Capacitors Posted: Thu Jan
10, 2008 12:16 pm
Joined: Wed Aug 16, 2006
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
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.