A proper layout is critical for the operation of any switched mode power supply, especially at high switching frequencies. Therefore, the PCB layout of the TPSM8282x/TPSM8282xA demands careful attention to ensure best performance. A poor layout can lead to issues like bad line and load regulation, instability, increased EMI radiation, and noise sensitivity. Refer to the Five Steps to a Great PCB Layout for a Step-Down Converter Technical Brief for a detailed discussion of general best practices. Specific recommendations for the device are listed below.
- The input capacitor should be placed as close as possible to the VIN and GND pins of the device. This is the most critical component placement. Route the input capacitor directly to the VIN and GND pins avoiding vias.
- Place the output capacitor ground close to the VOUT and GND pins and route it directly avoiding vias.
- Place the FB resistors, R1 and R2, and the feedforward capacitor CFF close to the FB pin to minimize noise pickup.
- The recommended layout is implemented on the EVM and shown in its TPSM8282xEVM-080 Evaluation Module User's Guide
- The recommended land pattern for the TPSM8282x/TPSM8282xA is shown at the end of this data sheet. For best manufacturing results, it is important to create the pads as solder mask defined (SMD), when some pins (such as VIN, VOUT, and GND) are connected to large copper planes. Using SMD pads keeps each pad the same size and avoids solder pulling the device during reflow.