CM3202−02

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APPLICATION INFORMATION (Cont’d)

PCB Layout Considerations

The CM3202−02 has a heat spreader (exposed pad) attached to the bottom of the WDFN8 package in order for the heat to

be transferred more easily from the package to the PCB. The heat spreader is a copper pad with slightly smaller dimensions

than the package itself. By positioning the matching pad on the PCB top layer to connect to the spreader during manufacturing,

the heat will be transferred between the two pads. Thermal Layout for WDFN8 package shows the CM3202−02 recommended

PCB layout. Please note there are four vias to allow the heat to dissipate into the ground and power planes on the inner layers

of the PCB. Vias must be placed underneath the chip but this can result in solder blockage. The ground and power planes need

to be at least 2 square inches of copper by the vias. It also helps dissipation if the chip is positioned away from the edge of the

PCB, and away from other heat−dissipating devices. A good thermal link from the PCB pad to the rest of the PCB will assure

the best heat transfer from the CM3202−02 to ambient temperature.

Figure 2. Thermal Layout for WDFN8 Package

Vias ( 0. 3 mm Diameter)

Thermal PAD

Solder Mask

Pin Solder Mask

Top Layer Copper

Connects to Heat Spreader

Bottom Layer

Ground Plane

Top View