Ed, I would be interested in what components you are using. At the temperatures you are listing, I would believe that the devices would be at their max junction temperatures (if they are fully loaded?). I think that Rockwell (maybe Honeywell?) was making some 300 C (operating) environment parts for downhole drilling that may withstand some of your temperatures. At 105C, do you have a heatsink or a fan? Just curious. Maybe you can share some of your results? Thanks. Max Bernhardt Woodward Governor Co. ---------- From: Ed Holton To: [log in to unmask] Subject: [TN] High Temperature application