| 摘要 |
PURPOSE:To select an arbitrary bit, and to realize the so-called nonvolatile RAM capable of the writing and reading of data by controlling the voltage of the control gate electrode of a floating gate type MIS type transistor by select signals from the outside. CONSTITUTION:For write data, X and Y1 are given program voltage VP (such as 20V), and Y2 is brought to 0V. When X and Y1 are given reading voltage VR (sucg as 5V) and Y2 is brought to 0V for read data Q1 and Q3 are at ON, the drain voltage VD of Q2 is brought to VR and control gate voltage VCG is brought to 0V. Accordingly, the presence of drain currents is detected, and data are read. For erase data, X and Y2 are given VP, and Y1 is brought to 0V. The transistor Q3 for control forms an AND circuit bringing the VCG of the memory transistor Q3 to high-level voltage VP only when X and Y2 are given high-level voltage VP, selects only the memory transistor Q2 positioned at the intersecting point of the bit line X and the word line Y1, and erases data. |
