Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
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Below are all of the forum threads, including all
the responses to the original posts.
Post subject: AMPLIFIER_200_400MHz Posted: Thu Nov 03, 2005 5:44 pm
Joined: Thu Nov 03, 2005 5:34 pm
I want to make about following parameters amplifier :
I need relating information:
- the influence of temperature on parameters the VDMOS, LDMOS.
- the selection of transistors (what firm ???)
- on what was one should be careful,
I found the solution firms polyfet, motorola, philips, macom.
Are yet some firm ??
thanks for information
Post subject: Posted: Sat Nov 05, 2005 11:23 am
Joined: Mon Jun 27, 2005 2:02 pm
The vendors you mentioned are the right ones. You should carefully check for the right device. Most of the vendors provide an application circuit for each device. The most important part of a PA circuit are the matching networks in the input and output. These networks also are designed for the required BW of operation. Your BW is octave, which is very wideband. So you should carefully examine this issue.
You should also pay attention to the bias feesing circuit. There should be a good isolation between the the RF output and the DC supply, and the bias level should be adjusted to provide the required linearity and output power level.