MULTI-BIT READ ONLY MEMORY CELL SENSING CIRCUIT

摘要

Multi-bit read only memory sensing circuit (10). A plurality of storage transistros (30, 32, 34, 36) are arranged in rows (28) and columns (20, 22) and each have a predefined permanent threshold voltage. A plurality of reference transistors (40, 42, 44) are provided. Circuitry (100, 102, 104, 106) is provided for selectively comparing the output voltage of ones of the plurality of reference transistors (40, 42, 44) to the output voltage of the plurality of storage transistors (30, 32, 34, 36) to thereby determine the voltage level stored in each of the plurality of strorage transistors (30, 32, 34, 36).