With the use of OSP becoming more commonplace, a concern has been raised
as to how chassis ground lands surrounding hardware mounting holes are
protected from corrosion in a high reliability commercial assembly. Is
OSP adequate for long term corrosion protection for a ground land? Per
my understanding, OSP is used to provide short term protection to SMT
lands, has a shelf life and is not intended to be left on the PCB
assembly after SMT reflow.

In the past, HASL (hot air solder leveled) was adequate in providing the
necessary corrosion protected metallic contact for hardware conducted
chassis ground. If a PCB is produced with OSP instead of HASL, then
there is no provision for the ground lands to be solder coated. One idea
that comes to mind is to include the lands in the solder paste artwork.
Is this practical? I realize that the PTH (plated thru hole) will still
lack solder coating, but a circular relief can be provided within the
land and around the hole to allow it to be an NPTH (non plated thru
hole).

How are my colleagues addressing this issue?
Chris Taylor
LXE, Inc.
125 Technology Parkway
Norcross, GA 30092
(770) 447-4224 X3242 v
(770) 447-6928 f
[log in to unmask]

################################################################
DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE DesignerCouncil <your full name>
To unsubscribe:   SIGNOFF DesignerCouncil 
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
################################################################