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 D1 component on the board first.
- Use a small size ceramic capacitor for COUT.
- Make the switching loop (COUT to D1 to SW to PGND to COUT) as small as possible.
- Leave a copper area near the D1 diode for thermal dissipation.
- Put the RVCC resistor in series with
the CVCC capacitor as near the device as possible between the VCC and
- Connect the COMP pin to the compensation components (RCOMP and CCOMP).
- Connect the CCOMP capacitor to the analog ground trace.
- Connect the AGND pin directly to the analog ground plane. Connect the AGND pin to the RMODE, RUVLOB, RT, CSS, and RFBB components.
- Connect the exposed pad to the AGND pin under the device.
- 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.