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Design >> RF Design >> Simulating a mixer in spectre RF
https://designers-guide.org/forum/YaBB.pl?num=1377025620

Message started by mixed_signal on Aug 20^th, 2013, 12:07pm

Title: Simulating a mixer in spectre RF
Post by mixed_signal on Aug 20^th, 2013, 12:07pm

Hi,
In cadence tutorials they recommend to match mixer output using an ideal Balun to 50 ohm. For this you need to know the magnitude of output impedance (Zout of mixer). How do you find the mixer output impedance?

Or just do a transient simulation for different values of termination resistor of 1:1 balun?

Title: Re: Simulating a mixer in spectre RF
Post by aaron_do on Aug 20^th, 2013, 5:50pm

Hi,

are you designing a standalone mixer or is it part of an SoC? If it is not standalone, I don't think you need to match the output. You should terminate the mixer with its real loading conditions to get an accurate measure of its performance.

In order to find the output impedance, you can run a PSS+PAC analysis. The impedance is found like in the picture below.

Note that if you decide to terminate the mixer using the balun + port, then its even easier to check the output impedance as you can just run PSS + PSP analysis and plot Z or Y parameters.

regards,
Aaron

P.S. here is an earlier discussion on the same topic:
http://www.designers-guide.org/Forum/YaBB.pl?num=1240334878/18