Genesis Technology USA, Inc. Heatsink Technologies November 2,

2 As board mounted chips grow in speed, the need for shielding the chip has become an increasing need to meet global regulatory guidelines. When chips need to be shielded as well as requiring a heatsink, this presents a problem that is not ideal for shielding or heat transfer. A popular way to remove heat from a shielded area is to add a heatsink on top of the shield cover. This is a very inefficient way to remove heat from the chip. The shield is typically made with cold rolled steel and steel is not a very efficient conductor of heat. The most effective way to remove heat from a chip is direct contact between the heatsink and the chip. Genesis has come up with a unique way to remove heat from chips that need cooling as well as shielding. Overview

Typical Heatsink Application November 2, Heainks need to be mounted directly to the heat producing chip for the most tsefficient removal of heat from the device. Heatsinks are mounted on a chip in various ways. - Thermal Adhesive -Solder Pins -Push Pins with springs -External clips For heatsinks to function at their most effective level there needs to be constant pressure applied to interface between the heatsink and chip. Therefore the most efficient cooling is accomplished by using an external clip or push pins with springs.

Heatsink Styles November 2, Heatsink with push pin attachment

Heatsink Styles, continued November 2, Heatsink solder pin attachment Heatsink with thermal adhesive attachment

Heatsink Styles, continued November 2, Heatsink with external clip

Heatsink Styles, continued November 2, In addition to different mounting styles for heatsinks, heatsinks can come with different styles of fins. The style of fin affects the performance as well as price. Heatsinks have fins and the fins are the method by which the heatsink removes heat from a device. The fins have different shapes depending on the manufacturing method. Basic fin styles are: -Straight fins -Straight fins with cross cut -Straight fins with cross cuts to form pin fins -Pin Fins -Elliptical shaped fins -Heatsink with attached fan -Heatsink with embedded copper slug or heat pipe

Heatsink Styles, continued November 2, Each type of fin has it advantages. -Straight fins: The least expensive type of fin to produce. Its limits are limited surface area to dissipate heat. -Straight fins with cross-cut: This type of fin adds cost but has the advantage of additional surface area to help with heat dissipation. -Straight fins with cross-cuts to form pin fins: This type of fin has even more surface area but comes with additional cost. -Pin fins: This type of fin had a lot of surface area and one additional advantage of being not dependent on fin orientation. This type will have higher tooling costs and would be more suited to high volume assemblies. -Elliptical fins: This type of fin also has a lot of surface area but relies on the fin shape and airflow to help dissipate heat. Tooling costs are high for this type. -Heatsink with embedded copper: This type of heatsink is used to help with higher power devices and can be applied to all the fin types listed above. -Heatsink with attached fan: This type of assembly is used for high power devices.

Heatsink Styles, continued November 2, Heatsink with Straight fins and Cross cut Heatsink with Straight fins

Heatsink Styles, continued November 2, Heatsink with Straight Style Fins and cross cut to form pin fins Heatsink with Pin Style Fins

Heatsink Styles, continued November 2, Heatsink with fanHeatsink with elliptical fins

Heatsink Styles, continued November 2, Heatsink with embedded copper Heat pipe or heat slug

Genesis Heatsink/Shield solution November 2, Here is an example of Genesis heatsink design that solves the heat transfer problem from high speed chips that are shielded. This method has a two piece shield over the chip and a cutout in the shield cover that allows the heatsink to touch the chip directly. This is a much more efficient method to remove heat from the chip as compared to mounting a heatsink on top of a shield. DDR3 memory is also inside the shield. See example below.

Genesis Heatsink/Shield solution November 2, These two examples show direct contact bosses for the heatsink to touch the chip directly. The example on the left is for steel cased chips and the one on the right is for glass topped chips. The construction of the boss is designed to prevent any damage to the glass during assembly.

Genesis Heatsink/shield Solution, continued November 2, Another style heatsink that utilizes the sink as a shield cover and thermal gap filler material to contact the chip directly. EMI gasket material is applied on the perimeter.

General Heatsink Comments November 2, Most heatsinks are custom designed for each customer/application -Quick turnaround for design and production parts -Low-cost tooling