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Simulators >> Circuit Simulators >> Differential LNA
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Message started by repah on Mar 26^th, 2015, 9:12pm

Title: Differential LNA
Post by repah on Mar 26^th, 2015, 9:12pm

Hello,

I am designing a differential CMOS LNA with a 60ohm differential source impedance and a 200ohm output impedance.

When I am sizing by devices and doing simulations, what impedance should I use in Cadence's ports ? Should I design a half of the differential LNA and then add the other half ? What approach is best ?

Any advice or resources would be helpful.

Thanks!

Title: Re: Differential LNA
Post by Ken Kundert on Mar 27^th, 2015, 2:55pm

You should use an ideal balun at the input and output to decompose the input and output into separate differential and common-mode components and drive them separately. You said the input source has a 60Ω differential source impedance, so make the port connected to the differential port of the input balun 60Ω. You will also need to connect something to the common-mode port to model the common-mode source impedance. Do the same for the output.

See A test bench for differential circuits for further details.

-Ken