Layout is a critical portion of good power supply design. The following guidelines helps users design a PCB with the best power conversion performance, thermal performance, and minimized generation of unwanted EMI.

1. The feedback network, resistors R1 and R2, must be kept close to the FB pin and away from the inductor to minimize coupling noise into the feedback pin.
2. The input capacitor C_IN must be placed close to the V_IN pin. This reduces copper trace inductance which affects input voltage ripple of the IC.
3. The inductor L1 must be placed close to the SW pin to reduce magnetic and electrostatic noise.
4. The output capacitor C_OUT must be placed close to the junction of L1 and the diode D1. The L1, D1, and C_OUT trace must be as short as possible to reduce conducted and radiated noise.
5. The ground connection for the diode, C_IN and C_OUT must be tied to the system ground plane in only one spot (preferably at the C_OUT ground point) to minimize conducted noise in the system ground plane.
6. For more detail on switching power supply layout considerations, see Application Note AN-1149, Layout Guidelines for Switching Power Supplies.