In PCB Design, thermal pad is also called as cross pad or hot air pad. Here are two situations where a thermal pad must be used in PCB design:
1. The pad is connected with earth wire,the cross pad is able to reduce the connection area of ground wire and heat dissipation of the pad during soldering so that it is much convenient to solder;
2. The PCB requires SMT via machine and the machine is a reflow welding machine; Adopting thermal pad, it will prevent cold soldering or PCB peeling due to excessive heat dissipation (Considering this reflow process need more heat to melt the solder paste).
