VOLATILE ELECTRICALLY ALTERABLE SEMICONDUCTOR MEMORY FOR ANALOG AND DIGITAL STORAGE FOR ANALOG AND DIGITAL STORAGE

摘要

A method and apparatus for achieving an analog memory location in a non-volatile memory array.;This memory array consists of a memory cell that utilizes Fowler-Nordheim tunneling for erase and uses thermal electron injection for programming. Writing to the cell is performed by an initial erase followed by a control sequence for the program operation in which the cell is programmed microcontrolled. The storage voltage is read after each programming step and the sequence of program steps is terminated when the read voltage from the cell is equal to or slightly higher than the desired analog level. The read condition for the cell applies a positive voltage to the drain or common line and applies a positive voltage to the control gate. The source is connected to the negative (ground) power supply through the load device. The output from the cell is the actual voltage present at the source node.