How to simulate IIP2 of an LNA in Cadence?

[estradasphere]

could someone explain me how to simulate IIP2 of an LNA in cadence?

thanks in advance.

 

[mbyoussef]

lna iip2

It's the same as IIP3 except that your IM tone would be at |f1-f2|.

I have to mention that IIP2 is not important forLNAs because the IM2 at the output will be upconverted after the first mixing stage and will reside out of your band of interest.

 

[khouly]

iip2 lna

the IIP2 is also very important for the zero IF receivers

khouly

 

[hmsheng]

lna iip2 simulation

For zero-IF receivers the IIP2 of mixer is important but IIP2 of LNA should have less effect. Right?

 

[estradasphere]

simulating lna im2

It's the same as IIP3 except that your IM tone would be at |f1-f2|.

I have to mention that IIP2 is not important forLNAs because the IM2 at the output will be upconverted after the first mixing stage and will reside out of your band of interest.

Thanks for the replies. However, I actually want to know how to plot IIP2 curve using Analog Artist. I have two large signals in front of my LNA with 10 MHz spacing. In Analog Artist I couldn't find an option to plot IP2, if you make a power sweep. You can only plot IIP3 and P1dB, I think.

 

[fanshuo]

lna, zero if

I did not use the analog artist before.
I think you can plot it in SpectreRF

and if you use a differential LNA then you can not find the 2nd order product, because it is canceled assuming perfect matching

you have to run monte carlo simulation to find it or just use some rough estimation

 

[khouly]

iip2, zero if

For zero-IF receivers the IIP2 of mixer is important but IIP2 of LNA should have less effect. Right?

also it is critical , coz the feed through in the mixer , will pass the IM2 prodccuts in LNA to the baseband

in real world , there is no 100 % match so the differential LNA will have IIP2 as well

khouly

 

[estradasphere]

zero if lna

For zero-IF receivers the IIP2 of mixer is important but IIP2 of LNA should have less effect. Right?

also it is critical , coz the feed through in the mixer , will pass the IM2 prodccuts in LNA to the baseband

in real world , there is no 100 % match so the differential LNA will have IIP2 as well

khouly

does nobody know how to plot IIP2 in cadence with power sweep?

Anyway, thanks a lot for the answers!

 

[hmsheng]

lna iip3 iip2

Given 2 tones input signal, for example frf1=1GHz, frf2=1.1GHz. and sweep input power, Prf=-60dBm to 30dBm. Then run PSS. After simulation finished plot IIP2 curve as following figure. Here the fundmental tone is 1GHz or 1.1GHz and the second intermodulation tone is 100MHz.

 

[M.B.]

iip2 im

Hello,

In order to simulate the IIP2 with Cadence, you do the same when you calculate IIP3. But you choice the order of intemodulation which is 2.
The attachement file can help you.

Good work