A 1.2V 10UA SINGLE-ENDED LOW POWER COMPACT SENSE AMP FOR HIGH DENSITY LOW VOLTAGE FLASH MEMORIES
Original Publication Date: 1999-Jun-01
Included in the Prior Art Database: 2002-Aug-19
It is unavoidable in high density flash memory design to use a low voltage low current sensing scheme with minimum bitline on-pitch selection cir- cuit as the flash technology continues to scale down and the memory size increases. This is because 1) the bitcell current is reduced in line with the finer pitch while the bitline capacitance is increased; 2) the performance gain by scaling is limited by the tight layout pitch of peripheral circuitry; 3) dynami- cally sensing schemes impose a speed limit by adding periods of precharging operations. The fol- lowing sections describe a new approach to address these problems: (a) The new circuit shown in Figure 1 achieves data sensing at relatively high speed with relatively low power consumption, by utilizing a static current sense amplifier and eliminating precharge periods required for dynamic sensing schemes, unlike prior art using direct voltage sensing with one or more bitline precharge and/or discharge phases (s= HI, PI).