10.1 Layout Guidelines
Use the following guidelines:
- Bypass the VDD and VIO pin to ground with a low-ESR ceramic bypass capacitor. A ceramic X7R dielectric capacitor with a value of 0.1 µF is recommend.
- Place the VDD, VIO, GND, and DGND pins as close to the device as possible. Take care to minimize the loop area formed by the bypass capacitor connection and the VDD, VIO, GND, and DGND pins of the IC. See Figure 42 for a PCB layout example.
- Bypass the CLDO pin to the digital ground (DGND) with a ceramic bypass capacitor with a value of 56 nF.
- Connect the filter capacitor that is selected using the procedure listed in the Selecting a Filter Capacitor (CFA and CFB Pins)section between the CFA and CFB pins. Place the capacitor close to the CFA and CFB pins. Do not use any ground or power planes below the capacitor and the trace connecting the capacitor and the CFx pins.
- Use two separate ground planes for the ground (GND) and digital ground (DGND) for a star connection as recommended. See Figure 42 for a PCB layout example.