Please help me about guard-ring issues

[rf_usn]

Hi all,

I am now designing RF part in the SoC. We all know that the guarding is needed for noise isolation. I have found some papers discussing about the effect of guard ring's width on the isolation. Ex. in the paper "On the P+ guard ring sizing strategy to shield against substrate noise" published in RFIC symposium in 2007, they say that starting from a guarding width above 16 um, the isolation saturates with the guard ring width. Now, let's say that we have 2 blocks that need to be isolated by guard ring; then my question is what is the typical distance between two blocks? Can anyone show me the reference about that? Thank you very much in advance.

Best regards,

rf_usn.

 

[Teddy]

I don't know how others but in my experience the bes "shield" is the distance. In critical circuitry like I usualy do "tripple" guardring (P+ / N+ / P+) and try to keep as much of "empty" substrate without any active device or guardring with thick oxide as possible. Since die is limited I am trying to get spacing of 50um - which seems to isolate quite well.

 

[rf_usn]

Thanks Teddy very much.

 

[k_90]

hi rf_usn

Where would I get a copy it that paper?

k_90@yahoo.com

 

[rf_usn]

hi k_90,

If you want, I can send you buy email.

Added after 5 minutes:

hi k_90,

I am trying to upload that paper here.