One of our board vendors is proposing a change from difunctional FR4 (ED103,
neutral color) to polyfunctional FR4 (ED402, yellow color). Other than the
color difference, the only other change I see is a slight improvement in Tg
and CTE. The boards involved in this change are 4 and 6 layers (primarily
power and ground on the inner layers). Does anyone have experience with
polyfunctional FR4 that would care to comment?

Also, would the material designation for the polyfunctional FR4 be "L25",
even though the Tg is 140 C?

Thanks in advance for any responses.



Michael Blackburn, Sr. Designer          www.novar.com
Novar Controls Corp.                     330.670.5584 (voice)
3333 Copley Road                         330.670.1021 (fax)
Copley, OH 44321

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