Saturday 14 June 2014

Thermal paste/compound - A small note

Thermal paste is a heat sink compound used on top of the processors (whether it be graphical or central processor), regulators for heat to follow smoothly to external medium. The mechanical designers suggest using a heat sink based on the thermal calculations. The principal behind using a heat sink in that the operating temperature of the device should not exceed the maximum specified ratings in the datasheet.

Operating temperature of a specific heat generating device is calculated by summation of junction temeparature and heat generated (Heat generated is the product of thermal resistance and power of operation). When this sum exceeds operating temperature specification that effect is catstrophic and can lead to device failure.

So, we have to use heat sink on top to enable the heat to escape from the device. Keep in mind that thermal paste is filling the imprefections of heat sink. The heat sink will be mounted on top of the device. Even though the heat sink is placed on top of device touching it there will be a air gap in between. Air is always a poor conductor of heat in which case another media must enable smooth heat flow. For this purpose we use a thermal paste. Thermal paste is a highly heat conductive paste.You mave have a large heat sink with exception fin structure for smooth heat flow, but, without a thermal paste the entire cost you have put on heat sink is a mere waste.

The thermal paste applied on top can be of different types. These can be electrically conductive as well as non-conductive. In a electronic board, it is always prefferable to use a non-conductive type. Cermaic based paste is one type of thermal paste. Arctic silver is the most preffered thermal paste.

What is Integrated Heat Spreader?
Keep in mind that the modern processors have a metal kind of enclosure for heat flow assistance. This we call a integrated heat spreader (IHS).

I already have a heat sink compound on the device. How do i clean it?
Usin Isopropyl Alcohol. Use a isopropyl dipped smooth cloth to rub off the paste.

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