日本語
Laminate suppliers only list one "Dielectric Strength" so I assumed that orientation didn't matter.
Then I discovered that there are two voltage breakdown tests. Test method IPC TM-650 2.5.6.2 is used for testing perpendicular to the plane and 2.5.6 parallel to the plane.
The 2.5.6 test appears to have a much lower passing threshold. So much so that IPC2221B guidelines for internal clearances come into question.
Does the claimed "Dielectric Strength" value of a PCB laminate really only apply to voltages perpendicular to the plane (2.5.6.2)?
Is there another name for the test results of 2.5.6?
Thank you.
- Comments(1)
A****min
Mar 17.2020, 10:38:20
The difference between the two is related to a phenomenon usually called "surface flashover". You can look that up - not an extremely simple thing - but basically, voltage breakdown between conductors on the surface of an insulator occurs at much lower voltages/lower distances than through the material (perpendicular).
