Designer’s Guide Community

‹ Previous topic | Next topic ›

Pages: 1

Differential LNA (Read 2014 times)

repah

Community Member

Offline

Posts: 68

Differential LNA
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!

IP Logged

Ken Kundert

Global Moderator

Offline

Posts: 2384
Silicon Valley

Re: Differential LNA
Reply #1 - 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

IP Logged

Pages: 1

‹ Previous topic | Next topic ›