An adjustable output driver with a self-recovering Vpp generator for a 4M/spl times/16 DRAM

An adjustable output driver with a self-recovering Vpp generator for a 4 M/spl times/16 DRAM (dynamic random-access memory) is presented. Its driver characteristics can easily be changed between fast mode and slow mode in the assembly process. The driver with a small inductance load operates 2.5 ns faster in fast mode than in slow mode, and the driver in slow mode reduces the initial drive current and prevents ringing waveforms even with large inductance load. With a 5 pF capacitance load and 20 cm wire, the ringing amplitude in slow mode is reduced to 1/3 that of the fast mode. Users can choose the operation mode of the output driver according to their application. The self-recovering Vpp generators feed 16 output drivers and control the generator capacity according to the data pattern to supply the same amount of Vpp charge consumed by output drivers. The Vpp generator saves 3.9 mA on average at a 25 ns read cycle.