Unless you have a requirement or other reason to keep them isolated It
would be best to connect them together.
If you decide to keep them them isolated then add multiple capacitors
between signal and chassis ground at each chassis connection point that can
be populated with different value capacitors or zero ohm resistors. Another
option is to have a chassis ground plane layer in your PCB that is
connected to signal ground at multiple points with capacitors. If you don't
have a solid RF connection between signal and chassis ground then there can
be an RF potential between the two grounds that can radiate if you have
antenna structures such as slots in your enclosure or external cables.
Joel
On Wed, May 9, 2018 at 9:16 AM, Guru Shankara <gurushankara@xxxxxxxxxxx>
wrote:
Hi Experts,
I am working on a modem design that is powered by an AC/DC supply
(isolated).
The design includes a base board that hosts a mezzanine/daughter card and
both the baseboard and the mezzanine cards are powered by 12V DC.
The chassis walls and misc. mechanical hardware have a conductive coating
on the inside and will be connected to the chassis/safety/earth ground of
the AC/DC power supply.
As the name implies, the chassis/safety/earth ground provides for safety
of the operator if there is a situation where the higher voltage side line
of the AC/DC supply rips off and makes contact with the chassis.
So, I prefer NOT to connect the board logic ground to the
chassis/safety/earth ground of the supply.
Any thoughts on if I should connect them together or not?
Also, if they need to be connected, is there a recommended method?
Really appreciate your help.
Thank you,
Gurushankar
------------------------------------------------------------------
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
