Problem in RFCMOS Layout
I have question regarding RFCMOS Layout. If i will placed three 2nH indcutor next to each other with 25um spacing between each other. does it create mutual inductance and lower the indctance of each inductance?
will there any problem in terms of layout issue ? what are the major solutions to avoid any mismatch which will affect the performance of LNA.
Hello!
You will get some coupling, and it depends on the connection of the three inductors what the overall effect will be. You might want to do an EM analysis of the three inductors together, so that the coupling is included in the model.
Best regards
Volker
your remedy is correct but I do not have much time now.
is there any solution like "rule of thumb", that i can use to avoid much coupling.
I will tell you where exactly these three inductor sitting insde the circuit.
One is First stage RF Choke inductance (Load Inductor)
Second is interstage between first and second stage
and third is Second stage RF choke
I kept good distance between them to avoid any distrabance. but, Still i am phobic about it.
Hello again,
I set up a quick test case in Sonnet with a generic technology and simulated the coupling. This are 2nH inductors with a distance from 20μm ... 50μm.
The plot shows the crosstalk (transmission S21 ) with 50 ohm ports.
The curve at 20μm spacing corresponds to a coupling factor k of 0.03
I do not know how sensitive your circuit is to this level of crosstalk.
Best regards
Volker
VOlker,
I really appreciated your help. Thanks a lot.
I have student version of Sonnet . I will try to analyze some more results.