email from: Mike Joyner


Hi Matt, your fabricators should be able to handle non-spoked connections to
the ground plane. Only argument that holds is for rework or service on
leaded or thru hole parts, smd parts are generally not a problem.. Spoked or
thermally relieved pads eat up a great deal of the ground plane for single
and 2 sided boards, although can be accommodated more readily with multi
layer designs with internal power/ground planes.



Photon Vision Systems
P.O Box 509
Cortland, NY 13045.
tel. 607.756.5200
fax 607.756.5319

www.photon-vision.com
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-----Original Message-----
From:   TechNet [mailto:[log in to unmask]] On Behalf Of Matthew Sanders
Sent:   Friday, October 09, 1998 8:22 PM
To:     [log in to unmask]
Subject:        [TN] RF soldermask defined pads

Hello,

My design engineers currently use a large amount of soldermask defined pads
in ground planes for RF boards. Based on discussions with my fabricator and
our assembly manufacturing folks, we'd like to get rid of designs like this
and use spoked thermal ties to ground instead. My RF engineers, however,
have concerns about doing this and losing material in their connection. Does
anyone have guidelines for boards like this? I guess I'd be interested in
hearing both sides: from the fabricator or assembler, how much material
would we need to remove from a connection to a pad to affect the
manufacturability; from the designer, how much material are you willing to
have removed without sacrificing any functionality.

Thanks for the help,
Matt

Matthew Sanders
PWB Procurement Engineer, Trimble Navigation Limited
[log in to unmask]

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