13.1 Layout Guidelines

Employing the thermally enhanced printed circuit board layout shown in Figure 58 insures good thermal performance of the solution. Observing good thermal layout practices enables the thermal pad on the backside of the QFN-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.

13.2 Layout Example

Figure 58 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 58. Recommended PCB layout of CDCM6208

Figure 59 shows two conceptual layouts detailing 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 59. PCB Conceptual Layouts

13.2.1 Reference Schematic

Figure 60. Schematic Page 1

Figure 61. Schematic Page 2

Figure 62. Schematic Page 3

Figure 63. Schematic Page 4