Need help designing a High Frequency Amplifier

drc_567

Joined Dec 29, 2008
912
... R12 ... is in line with the collector.
Reduce R12 to 100 ohms, but be prepared to adjust Vce, because it will be something different.
 

drc_567

Joined Dec 29, 2008
912
... you need more Ic current, so reducing R12 should do that. With the new R12 ... 100 ohms, hopefully you can fine tune Vce by adjusting Rvar2.
... not making any bets yet ... just something to try out.
 

Alec_t

Joined Sep 17, 2013
11,730
The frequency range is between 80-110 Mhz.
I need to amplify a 50mV pp AC signal to a 5V pp AC Signal
If you get it working you will likely be splattering radiation throughout the VHF radio band. You won't be popular with your neighbours or the authorities :eek:.
 

Thread Starter

Newbie_01

Joined Feb 26, 2019
12
... you need more Ic current, so reducing R12 should do that. With the new R12 ... 100 ohms, hopefully you can fine tune Vce by adjusting Rvar2.
... not making any bets yet ... just something to try out.

Tried but not working because I only have 25 mA coming from the source.
 

Thread Starter

Newbie_01

Joined Feb 26, 2019
12
Yeah, i have also calculated the Ampflification factor b which is Ic/Ib with the simulation results... And I should have an amplification of 130. So I really don´t get it where the problem is...
 

Ylli

Joined Nov 13, 2015
984
I don't think you are going to have much luck getting 40 dB of gain out of that. Miller capacitance is going to be a killer. Even going to a cascode configuration, 20 dB is a more realistic goal.
 
Top