The BGND pin is the boost ground connection for the controller. The effectiveness of the filter capacitors on the boost input and output depends upon the integrity of this ground return.
- Place the filter capacitors on BIN and VDD as close as possible to the device pins and BGND pin with short traces.
- Minimize the loop areas of the boost circuit and BGND to avoid coupling boost switching noise to other circuits.
- BGND should be tied to AGND at a location such that switching currents in the BGND return do not pass into the AGND network. Only low-ripple DC current should pass from BGND to AGND.