SLASEP7 May 2020 TMUXHS4212
On a high-K board, TI always recommends to solder the Power-pad™ onto the thermal land. A thermal land is the area of solder-tinned-copper underneath the Power-pad package. On a high-K board, the TMUXHS4212 can operate over the full temperature range by soldering the Power-pad onto the thermal land without vias.
For high speed layout guidelines refer to High-Speed Layout Guidelines for Signal Conditioners and USB Hubs, SLLA414.
On a low-K board, for the device to operate across the temperature range, the designer must use a 1-oz Cu trace connecting the GND pins to the thermal land. A general PCB design guide for Power-pad packages is provided in Power-pad Thermally-Enhanced Package, SLMA002.