LNA stability - ways of improving stability of a transistor

[venu.gongal]

LNA stability

I wanted to know the possible ways of improving stability of a transistor??

also Can I use this way for stsbilizing the transistor?? file attached

 

[BigBoss]

LNA stability

I think this resistor won't improve the stability.Instead, you should apply a little bit serial feedback onto emitter (source) by inserting a small resistor.
There are few ways to improve stability, you should check the optimum one depending on your topology and frequency and also transistor characteristics.

 

[venu.gongal]

Re: LNA stability

Hi
But i Have observed significant change in stability factor.

I am attaching the results.

But I wanted to know is it a proper way, does it effect any other circuit like the DC behaviour??

 

[Abhishekabs]

LNA stability

Can you please upload jpeg images? they have smaller size??

 

[Joel-Tang]

Re: LNA stability

The circuit you've shown is a very standard way of stabilizing an amplifier, yes. You'll pay for it in NF. You could increase the value of the resistor a little and this should use up some stability margin to improve your NF.

 

[alperuslu]

Potentially unstable transistors generally stabilized with series or parallel resistors. But adding resistor causes decreasing NF or Output power depending on where you add to resistor input or output port of transistor as mentioned above posts.If you want to stabilize your network over broadband I recommend you to use frequency selective stabilization network that is constructed using simple R-C or R-L . By using this stabilization you can increase stability where it needs without degrading the performance at frequencies that are already stable.

 

[buckaroo]

Oh come on, the resistor you added will deQ the inductor load greatly.