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Design >> RF Design >> about the pkg downbond inductor
https://designers-guide.org/forum/YaBB.pl?num=1158973304

Message started by jeetchu on Sep 22^nd, 2006, 6:01pm

Title: about the pkg downbond inductor
Post by jeetchu on Sep 22^nd, 2006, 6:01pm

for a simple one stage rf amplifier,such as LNA or driver,downbond inductor is used as the emitter degeneration .how much effection with the degeneration inductor on the gain and linearity?
I find the voltage gain is too sensitivity with the inductor value.the gain reduce 3dB when i set the indcutor from 0.5dB to 0.6dB.

Title: Re: about the pkg downbond inductor
Post by ACWWong on Sep 23^rd, 2006, 2:29am

Normally i would expect degeneration impedance increase of 20% to have the effect of reducing volatge gain by 1/1.2 (ie about -1.6dB) if gm*Zdegenertion>>1. Linearity would improve by a similar amount.

I think in your case you are having the additional impact of input mismatch (or at least change of input match) which is giving you the additional gain loss.

cheers
aw