Power modules without a baseplate

GERMANY: Power modules serve a wide and diverse range of purposes. For some applications, power density is a key factor. For others, efficiency or price may be the sticking point. But for all applications, reliability is a top priority.

Modules with solid baseplates made of copper or aluminum silicon carbide are commonplace. Cost concerns have also given rise to a new breed of module without a baseplate. Having examined different variants of modules, we can draw the following conclusions:

The longest component life may be achieved by keeping temperature ripple low. The load and environmental conditions are key factors. The smaller the number and the lesser the extent of thermal expansions, the greater the reliability. The CTE of materials should match. If thermal capacity is not an issue, a module without a copper baseplate is the right choice.

Modules with baseplates may still be necessary if brief spikes of high energy are expected. Each downward layer of material layer influences thermal spreading. Rth values stated in the datasheet are measured with a water-cooled heatsink and indicate the worst-case scenarios.