Explanation of LNA parameters: IP3, P1dB and OP3

Have a read through my linearity tutorial I think it explains all ! :)

For LNA's the most important parameters are (Of Course) Low Noise
Figure, and Gain. If you have Low Noise and High Gain this will keep
the whole systems noise close to the LNA's. For Example:

NFt= NF1 + (NF2-1)/G1 + (NF3-1)/(G1*G2) +.....

Now note if G1 is large, NF1 is low and NF2 will not greatly affect the
Systems noise( If you only use 2 Amps, use first 2 terms).

NFt = 2 + (5-1)/12 + (20-1) /(12*3) = 2.86

Remember the noise and gain for this EQ are in linear form, and you must
convert the answer to dB.

Also your systems application will determine what parameters are more important, so there is no perfect answer to this question.

Hope this helps.

Generally speaking, such parameters in LNA are not as important as in Power Amplifier.

There is simple practical relation between this parameters IP3(dBm) = P1dB(dBm) + 10dB,OP3(dBm) = IP3(dBm) + Gain(dB).Generally this parameters describe ability of LNA to work with high level signals.

A paper on Distortion in amplifiers. You can have all the answer and even more...

i think you should look up it for some books.
these are all basic questions in books.

You can reaserch google

the best book to read from about these parameters would be from
1) RF microelectronics by behzad razavi

and

2) RFIC design by calvin plett

i have designed 3.1-3.5 ghz lna through .7um mesfet technology. Noise figure is typically .83dB,gain is typically 18dB ,v.s.w.r is better than 1.8:1 at final design level.i want to reduce the noise figure. please give me some solution and comment about design.

They are used to measure the LNA linearity.

eecly

How to find the book:RFIC design by calvin plett ?

It depends on how far you are from best achievable NF for your process. What is NF opt acc to the manufacturer? Have you designed for NF opt? Or for a tradeoff between S11 and NF?

I could download the book: RFIC design by calvin plett ?

you can get RFIC design by plett from ftp.runnet.ru