11.1 Layout Guidelines

Layout of the application board significantly impacts the analog performance of the TRF3722 device. Noise and high-speed signals should be prevented from leaking onto power-supply terminals or analog signals. The TRF3722 device is fitted with a ground slug on the back of the package that must be soldered to the printed circuit board (PCB) ground with adequate ground vias to ensure a good thermal and electrical connection. The ground pins of the device can be directly tied to the ground slug pad for a low-inductance path to ground. Additional ground vias may be added if space allows. Follow these recommendations:

• Place supply decoupling capacitors physically close to the device, on the same side of the board. Isolate supply terminals with a ferrite bead.
• Maintain a continuous ground plane in the vicinity of the device and as return paths for all high-speed signal lines. Place reference plane vias or decoupling capacitors near any signal line reference transition.
• Power planes should not overlap each other or high-speed signal lines.
• Isolate REFIN routing from loop filter lines, control lines, and other high-speed lines.

11.2 Layout Example

Figure 139. Layout