A CMOS programmable analog memory-cell array using floating-gate circuits

The complexity of analog VLSI systems is often limited by the number of pin s on a chip rather than by the die area. Currently, many analog parameters and biases are stored off-chip. Moving parameter storage on-chip could save pins and allow us to create complex programmable analog systems. In this p aper, we present a design for an on-chip nonvolatile analog memory cell tha t can be configured in addressable arrays and programmed easily. We use flo ating-gate MOS transistors to store charge, and we use the processes of tun neling and hot-electron injection to program values. We have fabricated two versions of this design: one with an nFET injection mechanism and one with a pFET injection mechanism. With these designs, we achieve greater than 13 -bit output precision with a 39-dB power-supply rejection ratio and no cros stalk between memory cells.