The GND pad is used to dissipate
heat for the TPS25751S device. Connect the GND pins (11, 12, 14 and 31) to
the Ground pad (39) underneath the TPS25751S device. Connect the through
hole vias from the ground pad on the top layer to a copper pour on the
bottom layer to help dissipate heat. Additional vias can be added to improve
thermal dissipation.