11.1 Layout Guidelines

Employing the thermally enhanced printed-circuit board layout shown in Figure 64 insures good thermal performance of the solution. Observing good thermal layout practices enables the thermal pad on the backside of the VQFN-48 package to provide a good thermal path between the die contained within the package and the ambient air. This thermal pad also serves as the ground connection the device; therefore, a low inductance connection to the ground plane is essential.

Figure 64 shows a layout optimized for good thermal performance and a good power supply connection as well. The 7×7 filled via pattern facilitates both considerations.

Figure 64. Recommended PCB Layout of CDCM6208

Figure 65 shows the conceptual layout detailing the recommended placement of power supply bypass capacitors. If the capacitors are mounted on the back side, 0402 components can be employed; however, soldering to the Thermal Dissipation Pad can be difficult. For component side mounting, use 0201 body size capacitors to facilitate signal routing. Keep the connections between the bypass capacitors and the power supply on the device as short as possible. Ground the other side of the capacitor using a low impedance connection to the ground plane.

Figure 65. PCB Conceptual Layouts