Revised generic standards IPC-2221B on PCB design from IPC

The newly revised 170-page Generic Standard on Printed Board Design IPC-2221B from IPC provides a basis for the design of all types of printed boards and addresses areas as diverse as testing, via protection, test coupon designs and surface finishes. “We provided a lot of information that can help designers make decisions between surface finish alternatives,” said John Perry, IPC technical project manager. Perry added that descriptive data within the standard is augmented by a table that makes it easier to quickly compare the traits of various surface finishes. Industry’s focus on quality and reliability is addressed with an upgraded section on electrical requirement testing. “There are several pages of new material on electrical testing that explain the various types of tests available, including continuity, Hi-Pot and impedance,” Perry said. “Ultimately, the message is that no one test meets all requirements. Designers are encouraged to use two or three to ensure that they’re meeting user requirements.” IPC-2221B also provides details on via protection, which is becoming more important as the number of via holes on a typical board increases. Another significant addition to the revised standard is the new Appendix A that details a new set of test coupon designs that are utilized for lot acceptance and periodic conformance testing in accordance with performance specifi...