This application note is intended to help the system designer utilize the benefits of the FAN2011 and FAN2001 families of high performance step-down DC-DC regulators, to avoid PCB layout related problems and maximize overall system performance. The basic concept of “star grounding” is presented and ways of implementing star grounding for systems like a cell phone, are shown.
Ground wiring can often limit system performance by coupling noise from power elements into signal paths. This document addresses these issues, specifically regarding the finite resistance of grounding paths and inductively induced currents that create circulating ground loop currents.
The text details the "star grounding" technique as a solution to minimize DC offsets and noise. It provides specific guidance for designing PCB layouts for the FAN2011 and FAN2001 families, including separating signal grounds from power grounds at the star point and routing feedback signals away from high current paths.
The document helps system designers utilize the benefits of the FAN2011 and FAN2001 families of high performance step-down DC-DC regulators to avoid PCB layout related problems and maximize overall system performance.
The document presents the basic concept of star grounding and shows ways of implementing it for systems like a cell phone.
If large ground noise couples into the feedback signal, the device may become unstable and the output voltage will be out of regulation.