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

This paper describes an adjustable output driver with a self-recovering Vpp generator for a 4M×16 DRAM. Its driver characteristics can easily be switched between fast and slow modes in the assembly process. With a small inductance load, the driver operates 2.5 ns faster in fast mode than in slow mode. In slow mode, this driver reduces the initial drive current and prevents ringing waveforms even with a large inductance load. For example, with a 5-pF capacitance load and a 20-cm wire, the ringing amplitude in slow mode is reduced to 1/3 of fast mode. Users can select the output driver operating mode that best suits their application. The self-recovering Vpp generators feed 16 output drivers and control the generator capacity according to the data pattern to supply the exact amount of Vpp charge consumed by the output drivers. The Vpp generator saves 3.9 mA on average in 25-ns read cycle