[SI-LIST] Power planes, ground cutout and guard traces
- From: Michele Manotti <michele.manotti@xxxxxxxxx>
- To: si-list@xxxxxxxxxxxxx
- Date: Wed, 5 Nov 2014 10:24:26 +0100
Hi experts,
I'm designing a mixed signal board where the analog part is very critical
so noise and disturbances has to be minimized. I have three questions for
you:
1) All the board is powered with LDOs and between regulators' output and
power planes I'm about to place 0 Ohm resistor to be able to disconnect one
rail at a time in case of unwanted short due to production error. Does this
have counter effects? I mean having a wide power plane under loads and
decoupling capacitors connected with a narrow path (the resistor) to
regulators output.
2) Analog and digital parts share the same ground. In the common ground
plane I would insert a cut out between the two parts and make the two
grounds (actually the same) connection under the ADC. Just to be clear:
analog part is in upper right corner, digital one in lower right corner and
ADC in the left side and so the ground plane make a sort of C. Doing this
way some digital traces (switching eventually at tens of MHz) in inner
layers would cross the ground cutout (I can't move or remove them). Could
this approach add more noise instead of reducing it? Would you suggest
better techniques?
3) On top and bottom layers I have space to insert guard traces between
analog and digital parts in order to reduce crosstalk. What do you think is
the best way to accomplish this (leave trace floating, grounding it, how
many vias)?
Thanks a lot,
Michele
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
