| 摘要 |
A power supply system (15) incorporated in a dynamic random access memory device distributes a step-down power voltage (Vint) and a boosted voltage (Vboot) to a sense amplifier unit (13a) and a word line driver (12a) for allowing switching transistors of the memory cells to transfer the step-down voltage level to the storage capacitor without any voltage drop in read-out and write-in modes, and the switching transistors and the storage capacitors are subjected to inspections through a burn-in testing process before delivery from the manufacturing factory so as to actualize potential failure; however, either switching transistors or storage capacitors are insufficiently stressed in the burn-in testing process, and the power supply system changes the ratio of the boosted voltage to the step-down power voltage between the read-out and write-in modes and the burn-in testing process so that the switching transistors and the storage capacitors are sufficiently stressed. <IMAGE> |
