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https://designers-guide.org/forum/YaBB.pl Design >> RF Design >> Max power gain for LNA https://designers-guide.org/forum/YaBB.pl?num=1075846753 Message started by N Logan on Feb 3rd, 2004, 2:19pm |
Title: Max power gain for LNA Post by N Logan on Feb 3rd, 2004, 2:19pm If I designed an LNA with the input stage being a classical common source type (N-type) and then using a P-type as a unity gain current buffer. Now I am not quite sure how or what would be wrong, but if the 1st stage had an excellent voltage gain (i.e. biased to have such a low current since current inversely proportional to Av. And then for the 2nd stage I biased the P-type current buffer with a larger current. Now why will this not provide the best power gain? Or will it? thanks |
Title: Re: Max power gain for LNA Post by jdeng on Feb 12th, 2004, 4:22pm I'm not sure whether you have considered the effect of mismatch between first stage and buffer. |
Title: Re: Max power gain for LNA Post by n.logan on May 8th, 2004, 1:45pm Can I put it another way.- If I terminate the output to a large impedence I have a great voltage gain. If I matched it to 50 ohms I don't. How will I buffer the output so that I don't lose gain Av=GmRo Thanks |
Title: Re: Max power gain for LNA Post by naren on May 20th, 2004, 3:48am the 1st stage will see a load cap in the gate of the second stage. you need to cleverly tune out this capacitance int he gate of ur second stage CD buffer. and then match the CD buffer to a 50Ohm. I am doing same thing here and it works |
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