A proper layout is critical for the operation of
any switched mode power supply, especially at high switching
frequencies. The PCB layout of the TPS6286A06D device requires careful attention to make sure of
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
analog design journal for a detailed discussion of
general best practices. The following are specific recommendations
for the TPS6286A06D:
- Place the input capacitor as close as possible to the VIN and GND pins of the device. This placement is the most critical component placement. Route the input capacitor or capacitors directly to the VIN and GND pins.
- Place the output inductor close to the SW pins. Minimize the copper area at the switch node.
- Place the output capacitor ground close to the GND pin and route directly. Minimize the length of the connection from the inductor to the output capacitor. Connect the OUT pin directly to the output capacitor.
- Place the FB resistors R1 and R2 close to the FB pin and place R3 close to the VSET/MODE pin to minimize noise pickup.
- Make the connections from the input voltage of the system and the connection to the load as wide as possible to minimize voltage drops.
- Have a solid ground plane between GND and the input and output capacitor ground connections.