A 65ns 1Mb CMOS alternate metal virtual ground EPROM with dual reference sensing scheme and word line voltage regulator

The alternate metal virtual ground (AMG) has recently been introduced as a scaling concept for an EPROM array. The AMG cell size in a 0.8 mu m technology (2.56 mu m²) is smaller than the cell size on a conventional architecture implemented in a 0.6 mu m technology (3.6 to 4.4 mu m²). The implementation of the AMG architecture in a 1 Mb (128 K*8) EPROM design with a die size of 14mm² (3.2mm*4.4mm) using 0.8 mu m single metal CMOS technology is discussed. An access time of 65 ns is accomplished by a decoded precharge and a dual reference sensing scheme. A typical programming time of less than 10 mu s and a Vccmax of greater than 8 V are achieved with the word line voltage regulator (WLVR).