The RF section of this wireless module gets top priority in terms of layout. It is very important for the RF section to be laid out correctly to ensure optimum performance from the module. A poor layout can cause low-output power, EVM degradation, sensitivity degradation, and mask violations.

Figure 10-2 shows the RF placement and routing of the CC3220MODx module with external antenna.

Figure 10-2 RF Section Layout

Follow these RF layout recommendations for the CC320MODx device:

• RF traces must have 50-Ω impedance.
• RF trace bends must be made with gradual curves, and 90° bends must be avoided.
• RF traces must not have sharp corners.
• There must be no traces or ground under the antenna section.
• RF traces must have via stitching on the ground plane beside the RF trace on both sides.
• RF traces must be as short as possible. The antenna, RF traces, and the module must be on the edge of the PCB product in consideration of the product enclosure material and proximity.

For optimal RF performance, ensure the copper cut out on the top layer under the RF-BG pin (pin 31) is as shown in Figure 10-3.

Figure 10-3 Top Layer Copper Pullback on RF Pads