FR4 Temperature limitations?

[kombayotch2]

I have a high-temperature automotive application (150C ambient). I would like to keep the cost down and one of the things I'm considering is perhaps using one of the FR4 laminates with a very high Tg (such as IS410) instead of going the ceramic route. The board temperature would be below 175C as this is the max junc. temp. of the power parts.

Looking at the properties of some of these, one of the things that worries me is the z-axis expansion (up to 35% for some materials). That the vias could fail during repeated thermal shock tests, for example.

Doe anyone have any experience using FR4 at higher temperatures? What are the issues?

 

[Comcokid]

I suggest you check into one of the newer FR4 materials made for RoHS compliance. These materials are designed for the higher soldering temperatures of lead-free solders The Z-axis expansion can't be too great or the boards would never survive the the manufacturing process.

 

[MikeHalloran]

One way to keep the cost down is to use single layer boards. That also solves the via durability problem.



Mike Halloran
Pembroke Pines, FL, USA