When the thermal heat dissipation requirements of a design are very high, using an Aluminum backed PCB is a highly effective solution. This kind of design is capable to better translate thermal energy away from your design's components, therefore control your project's temperature. It is typically on the order of ten times more efficient at removing thermal energy from circuit components than the equivalent fiberglass backed board. This significantly higher level of thermal dissipation allows for higher power and higher density designs to be implemented.
More and more, Aluminum Backed PCBs are finding applications in high power/high thermal heat dissipation applications. Originally tasked for use in high power switching supply applications, aluminum backed PCBs have become very popular in LED applications. Examples of LED applications include traffic lights, general lighting and automotive lighting.
The use of an aluminum backed design (LED PCBs) allows for a higher density of LEDs in the board design and for the mounted LEDs to be driven at higher currents while still remaining within temperature tolerances. Using an Aluminum backed design can allow designers to decrease the safety margin used with power LEDs and derate said LEDs less than would be the case with a conventional PCB design. As with all components, the lower the operating temperature of the LEDs in a design the longer those LEDs can be expected to operate before failing.
Other applications for Aluminum backed PCB designs include high current circuitry, power supplies, motor controllers and automotive applications. Aluminum backed PCBs are the perfect thermal heat dissipation solution for any design that utilizes high power surface mount ICs. Additionally, they can eliminate the need for forced air and heat sinking, then ultimately lower design cost. Essentially, any design that can be improved by higher thermal conduction and better temperature control is a possible application for an Aluminum backed PCB.
Where as traditional PCBs use fiber glass substrates (FR4 is the standard substrate used by PCB fabricators), Aluminum backed PCBs are composed of an aluminum backing, a highly thermally conductive dielectric layer and a standard circuit layer. The circuit layer is essentially a thin PCB that has been bonded to the aluminum backing layer. As such, the circuit layer can be as complex as those mounted on traditional fiber glass backing.