To prevent thermal shutdown, TJ must be less than 150°C. The PCB layout is very important. Good PCB design can optimize heat transfer, which is absolutely essential for the long-term reliability of the device.
- Maximize the copper coverage on the PCB to increase the thermal conductivity of the board. The major heat flow path from the package to the ambient is through the copper on the PCB. Maximum copper is extremely important when there are not any heat sinks attached to the PCB on the other side of the package.
- Add as many thermal vias as possible directly under the package VBB and VOUT pads to optimize the thermal conductivity of the board.
- All thermal vias must either be plated shut or
plugged and capped on both sides of the board to prevent solder voids. To verify
reliability and performance, the solder coverage must be at least 85%.