The performance of switching converters heavily depends on the quality of the PCB layout. The following guidelines will help users design a PCB with the best power conversion performance, thermal performance, and minimize generation of unwanted EMI.

• Put the Q1, D1, and R_S components on the board first.
• Use a small size ceramic capacitor for C_OUT.
• Make the switching loop (C_OUT to D1 to Q1 to R_S to C_OUT) as small as possible.
• Leave a copper area near the D1 diode for thermal dissipation.
• Put the device near the R_S resistor.
• Put the C_VCC capacitor as near the device as possible between the VCC and PGND pins.
• Use a wide and short trace to connect the PGND pin directly to the center of the sense resistor.
• Connect the CS pin to the center of the sense resistor. If necessary, use vias.
• Connect a filter capacitor between CS pin and power ground trace.
• Connect the COMP pin to the compensation components (R_COMP and C_COMP).
• Connect the C_COMP capacitor to the power ground trace.
• Connect the AGND pin directly to the analog ground plane. Connect the AGND pin to the R_UVLOB, R_T, C_SS, and R_FBB components.
• Connect the exposed pad to the AGND pin under the device.
• Connect the GATE pin to the gate of the Q1 FET. If necessary, use vias.
• Make the switching signal loop (GATE to Q1 to R_S to PGND to GATE) as small as possible.
• Add several vias under the exposed pad to help conduct heat away from the device. Connect the vias to a large ground plane on the bottom layer.