A 32Mb -4b/cell analog flash memory supporting variable density with 3V-only supply and serial I/O

This 8M cells Flash EEPROM using the Analog Flash technology is able to store up to 32Mbit of digital data (4bit/cell). The fully integrated memory chip has a 3V-only power supply and a dual standard configurable serial I/O interface (SPI and I
²
C) to allow 6+1 pin packaging suited for small form factor removable memory card. The analog flash programming is managed by an embedded microcontroller. The chip is fabricated in a standard 3V 0.5µm common-ground NOR Flash-EEPROM process (2 polys, 3 metals) with channel hot electron programming and Fowler-Nordheim tunnelling erasing. The cell is 1.7×1.9µm
²
, the chip area is 13.5×6.1mm
²
.