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Design >> RF Design >> Spiral inductors and EM-noise
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Message started by Paul on Aug 10^th, 2005, 3:04am

Title: Spiral inductors and EM-noise
Post by Paul on Aug 10^th, 2005, 3:04am

Hello,

I am using spiral inductors for peaking purposes in a high-speed (GHz-range) amplifier and I was wondering whether it might pick up ambient EM noise that could perturbate the signal. The design is fully differential for supply and substrate noise rejection and the inductor therefor is a t-coil type structure.

Has anybody experienced such problems or suggestions to avoid this problem. Or isn't this a real issue after all?

Thanks in advance for your comments.

Paul

Title: Re: Spiral inductors and EM-noise
Post by neoflash on Nov 6^th, 2005, 6:01am

Generally it is not an issue, since the signal in your CML stage is digital signal instead of RF signal.

If you are treating with small signal such as LNA, you can add inductor ground shield, and place inductors far enough.

How far is enough? That is a question. I will use suggest 200um as the bottom line, if your inductor is 100um square.

Title: Re: Spiral inductors and EM-noise
Post by Paul on Nov 8^th, 2005, 12:01pm

Thanks for your answer, that's more or less what I was looking for.

Paul