output stage drain power voltage (VDDQ)

The power pin that is intended to supply power to the output transistors of the device to provide the potential and energy to drive the load applied to the data output (Q) pins or data input/output (DQ) pins. Other, non-data, output transistors may also be designated to be supplied by this power pin. The potential of VDDQ may be specified the same as or different from that of the primary device power pins (VDD).

References: 

JESD21-C#, 1/97