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How to plot IPN (IP3/2) without using PORT at Circuit OutPut

Last post Wed, Jun 6 2012 4:33 AM by RFQuery. 2 replies.
 Started by RFQuery 05 Jun 2012 07:09 PM. Topic has 2 replies and 3038 views
• Tue, Jun 5 2012 7:09 PM

• RFQuery
• Joined on Wed, Jul 20 2011
• Posts 89
• Points 1,270
How to plot IPN (IP3/2) without using PORT at Circuit OutPut
 Dear All, I was designing a LNA which is input matched to 50 Ohm.It is driving the next stage whose input impedance (MOS input) is very large (it is NOT 50 Ohm matched anyway).I want to plot this LNA's IIp3/2 using IPN curves. However for that Cadence requires a PORT to be used at the Output of the LNA.I could NOT understand why it has been done for PORT  ? Why it can't take voltage output and calculate/plot the IIP3/2 ?In chip design the components (inside the chip) need NOT to be matched but Cadence is still using the OLD fashion way of using matched PORT !!But anyway can anybody please tell how it can be done without using PORT at the output.Kind Regards
• Post Points: 20
• Wed, Jun 6 2012 2:33 AM

Re: How to plot IPN (IP3/2) without using PORT at Circuit OutPut
 The measurement on the form is measuring power-based IPN, whereas you presumably want voltage-based IPN. You don't have to have the output being a port - you can specify it as a voltage and tell the impedance to convert into a power, but maybe you just want to directly do a voltage-based measurement.I wrote a solution some time ago which describes how to do this, but I have been in discussion with R&D about getting this directly available (without needing the mapping described in the solution).Regards,Andrew.
• Post Points: 20
• Wed, Jun 6 2012 4:33 AM

• RFQuery
• Joined on Wed, Jul 20 2011
• Posts 89
• Points 1,270
Re: How to plot IPN (IP3/2) without using PORT at Circuit OutPut
 Dear Andrew,Thanks a lot.Kind regards,
• Post Points: 5