CM3202-02DE Datasheet, PDF (10/11 Pages) ON Semiconductor – DDR VDDQ and VTT Termination Voltage Regulator

CM3202−02
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.
Top View
Bottom Layer
Ground Plane
Top Layer Copper
Connects to Heat Spreader
Pin Solder Mask
Vias ( 0. 3 mm Diameter )
Thermal PAD
Solder Mask
Figure 2. Thermal Layout for WDFN8 Package
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