Is it possible not to connect the thermal pad of LP38513-ADJ and LP38503-ADJ (D2PAK-5 package) to Ground. This way only pin 3 will be used for electrical connection. Theramal performance will be ensured by an other way. LP38503-ADJ datasheet says that "The DAP must be connected to ground potential". LP38513-ADJ datasheet says that "The DAP is not internally connected to device ground and the DAP should be soldered to the Ground Plane copper".