Clarification about IIP3 measurement in ADS

[hari_preetha]

Dear Sir,
I designed low noise amplifier at 1.4 GHz using Avago ATF54143 transistor. I obtained gain of S₂₁ of 17.718dB at 1.4 GHz. Using the template of HB2 power swept in ADS, I have simulated source power, fundamental power, and third order power and using these values , I have drawn Pin v/s Pout graph. I have got the IIP3= 49.866dBm , and OIP3 = 66.138 dBm.
In data sheet of Avago ATF54143 at f = 2GHz min= 33dBm, typ= 36.2dBm, similarly f=900MHz, typ= 35.5 dBm.
I am confused with obtained values of IIP3=49.866dBm,and OIP3=66.138, Gain obtained (S21)= 17.718dB.
My question is, how to cross verify these obtained values IIP3 and OIP3 values correct or not.For 1.4GHz using ATF54143 transistor , what must be the maximum IIP3 and OIP3, we can get.Is there any formula for cross verifying these obtained values of IIP3 and OIP3 correct or not.If it is not correct , using ATF54143 transistor how much maximum IIP3 and OIP3 we must get
Some other LNA designed and tuned at some other frequency 915MHz, I have obtained the IIP3 =51dBm and OIP3=69.60dBm,gain(S21)=25dB. I have doubt on these values of IIP3 and OIP3, because I am getting the huge values of IIP3 and OIP3.
How to cross verify these values of IIP3 and OIP3 weather it is correct or not, can you clarify it. Related files of IIP3 and OIP3, I attached it.

 

[raju_kambar]

You may use the following equation

IIP3=P1dB+10
IIP3=OIP3-GAIN

 

[hari_preetha]

Dear Sir,
Someone can clarify it the above points in posting #1.

 

[hari_preetha]

Dear Sir,
Someone can give the closer answer to the posting #1 points

 

[BigBoss]

When OIP3 simulation is done, max. output power for each carrier should be 20dB lower-at least- than P1dB Output Power hence xIP3 equation is still valid.
For instance...
Let's say an amplifer G=20dB and P1dB=30dBm
Maximum allowable input signal(s) for OIP3 simulation will be
P1dB-20=>10dBm-Gain=-10dBm for each.
Otherwise Intercept Point will not be valid anymore..

 

[hari_preetha]

BigBoss Sir,
Thank you for your answer

 

[hari_preetha]

When OIP3 simulation is done, max. output power for each carrier should be 20dB lower-at least- than P1dB Output Power hence xIP3 equation is still valid.
For instance...
Let's say an amplifer G=20dB and P1dB=30dBm
Maximum allowable input signal(s) for OIP3 simulation will be
P1dB-20=>10dBm-Gain=-10dBm for each.
Otherwise Intercept Point will not be valid anymore..

BigBoss Sir,
Infact, I didn't clear, what you conveyed in the previous posting. What about Input Intercept Point (IIP3), what will be maximum IIP3, we can have. If we know Gain earlier. How to calculate IIP3 theoretically and practically,what must be the maximum IIP3.

 

[BigBoss]

BigBoss Sir,
Infact, I didn't clear, what you conveyed in the previous posting. What about Input Intercept Point (IIP3), what will be maximum IIP3, we can have. If we know Gain earlier. How to calculate IIP3 theoretically and practically,what must be the maximum IIP3.

Simple..

IIP3=OIP3-Gain

Since OIP3 can be measured or simulated and the Gain is already known, IIP3 can be extracted from these two by considering the conditions mentioned before..

 

[Chethan Chethu]

hw to obtain IIP3 and Compression point performance of an LNA using ADS tool..???? plzzzzzz help me..

 

[RealAEL]

If you use the HB2ToneSwptPwr schematic template (Insert > Template...) to set up a Harmonic Balance simulation of your LNA then the results generated include All the typical measurements like gain compression, IIP3 (also OIP3, IIP5 and OIP5) and much more.

 

[Chethan Chethu]

yeh.. i inserted HB2Tone in display template in my schematic.., but hw to plot IIP3 or P1 dB point..??