I am considering using a TLV75733PDRVR LDO to drop 4V to 3.3V while driving up to 1A, thus needing to dissipate around 0.7 watts. Would an additional heat sink be required in this situation, assuming the PCB provides a large copper plane well thermally connected to the TLV757P's thermal pad? Page 18 of its spec sheet was kinda vague on this. I am using a 4-layer FR4 board with 3 oz/ft^2 copper on its outer layers and otherwise standard PCB fab technologies. I can provide an array of plated vias (how many do I need?) under the device to conduct heat from the top layer to the bottom layer. How big of a total area of copper should exposed on the top and bottom layers to be ok with this amount heat dissipation? I don't know how to calculate this; any pointers would be a big help. Thanks heaps in advance.
Also, how does the answer change if this LDO were used to drop all the way down from 5V (again, providing 3.3V at up to 1A), thus needing to dissipate around 1.7 watts?