In a message dated 1/31/2002, Rick Busche writes:
> Does the application of a solder mask allow for a change from pollution > degree 2 to pollution degree 1? I understand that conformal coating > requires significant testing when used to reduce spacings per table 7, but > in this case I am only asking if solder mask can be used to improve the > pollution concern. > Hi Rick: You do not mention which standard you are looking at, but if it is one of the IEC 950 derivatives there are some clauses that specifically address the questions you have. For example, in EN 60950, Third Edition, clause 2.10.5.3 addresses printed circuit boards, and clause 2.10.6 addresses solder mask. To the extent you can use inner layers, clause 2.10.5.3 should provide you some of the relief you seek. I have not ever tried to qualify a solder mask under clause 2.10.6 due to the burden of the additional tests, but you may want to consider it. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 http://www.randolph-telecom.com
