Ralph,

Designs conforming to the IPC-D-275 will still comply with the replacement
standards IPC-2221/2222. The IPC-2221/2222 contains many new additions and few
technical changes. The technical changes would have tightened up some of the
numbers based on current industry capabilities. Therefore, any designs that
met IPC-D-275's looser numbers would certainly meet the new tighter
specification.

However, there are two areas that can potentially be a problem. The first area
is the reduction of copper plating in plated through holes for class 2
product. The minimum plating has been reduced to 20 um (0.0008 in) from 25 um
(0.001 in). If your product performance was just marginally passing with the
thicker plating, you may find failures should the same product be produced
under the new specification (IPC-6011/6012). I caution users to run test
boards before allowing the board fabricator to switch to IPC-6011/6012 on
thier products.

The second area of concern has to do with soldermask thickness. When the IPC-
SM-840 was revised it relocated application requirements to the IPC-6011/6012
since these requirements are mainly for the fabricator. In doing so, they
removed the minimum thickness requirement for class 2 product and recommend
that a minimum thickness be placed on the master drawing. Since there was a
default thickness built into the old standard, placing this requirement on the
master drawing has not normally been the practice of the industry.

As a result of these concerns, the IPC TAEC has recommended that an impact
statement be part of the release process for future revised standards. Mainly
to make the user aware of any potential problem areas.

Regards,

Gary Ferrari
Executive Director
IPC Designers Council
860-350-9300

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