What is the highest ambient opeprating temperature of TOP261EN?

Posted by: maxjason on 07/14/2009

Hello,

I want to know the highest ambient operating temperature of TOP261EN. My power supply will output 27.6V, 5A.Input is 102VAC to 132VAC.

Thanks,

Maxjason

Comments

Assuming you want to keep juntction temperature below 100C, the crtical component is the temperature of the heatsink near the TOP261. For your power level perhaps a 10 degree rise above heatsink, so heatsink itself should be limited to 90C. Whatever ambient causes heatsink to rise to 90C at full load and lowest specified AC input voltage will determine your max tolaerable ambient temp.

We do have customer with high ambient requirements (ovens and cook-tops for example). In these situation increasing the maximum IC temperature to 110 C is acceptable. Although the minimum thermal shutdown is 135 C the recommendation of 110 C allows for device to device variation in RDSon and variation in efficiency of individual power supplies due to other components.

Cheers

PI-Chekov

Is there any operating time requirement at high temperature, for example, if the component temperature is around 85C at full load, how long can it run?

Thanks again,

Maxjason