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Design >> RF Design >> Noise optimization for LNA
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Message started by aaron_do on Jun 3^rd, 2009, 2:38am

Title: Noise optimization for LNA
Post by aaron_do on Jun 3^rd, 2009, 2:38am

Hi all,

In my receiver design, I thought it would be a good idea to provide a separate ground pin for the LNA in order to improve prevent noise coupling through the ground line and substrate from other blocks. I should mention that in fact all blocks share the same substrate, but I do have the option of isolating the LNA with deep n-well.

So my questions are (assume ground 1 is the LNA ground, ground 2 is the rest of the blocks ground):

1) Should I connect the substrate around the LNA to ground 1 or ground 2?

2) The inductor has a patterned ground shield as part of the PDK. Should I connect this to the ground 1 or gound 2?

3) How should I isolate the LNA from the rest of the receiver? I am currently using P+ diffusion connected to ground 1 (should I use ground 2?). I have the option of using deep n-well.

4) Should I be using any isolation around the incoming RF lines for the LNA? If so, how?

Any other tips on how to get this grouding done properly would be greatly appreciated.

thanks,
Aaron