Improved non-volatile shadow storage cell with reduced tunnel device count for improved reliability

摘要

A non-volatile shadow memory cell utilizing a single isolation device (20), preferably of the Fowler-Nordheim tunneling type, for each non-volatile module. This is obtained by using a level shifting input/output circuit (42) which comprises two level shifters (66 and 68), the input terminals of which are connected to the output terminals D and D of the volatile storage cell, respectively, and the output terminals of which are connected to the Fowler-Nordheim device (20), either directly for level shifter (66) or the capacitor (C₂₆) for level shifter (68).