A 35 ns-cycle-time 3.3 V-only 32 Mb NAND flash EEPROM

Abstract

A 32 Mb NAND type flash EEPROM in 0.425 /spl mu/m CMOS achieves 35 ns cycle time for data read-out and programming data load by adopting a pipeline scheme. Metal-strapped select gates and boosted word line reduce read-out access time. Tight-programmed cell Vth distribution can be realized by program verify, using a simplified data register circuit. Multiple blocks can be erased at the same time by adopting erase block registers for each block. Simultaneous-erase verify for one block reduces total erase time. All funtions require only 3.3 V power supply.