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Abstract

A method for programming in parallel reference cells to be used for operating other cells of a memory cell array, the method including: a) reading each of the reference cells of a memory cell array with a sense amplifier, the sense amplifier providing an output indicative of a programmed state of the reference cell relative to another bit in the array, b) reading each of the reference cells of a memory cell array with a sense amplifier while using read conditions to determine if the reference cells have reached a target level, c) determining if a programming pulse should be applied to the reference cell by comparing the output of the sense amplifier to a predefined target '0' or '1', d) setting a buffer bit, corresponding to the output of the sense amplifier, in a sticky bit buffer to a first logical state if the reference cell needs to be programmed, and not changing a logical state of the buffer bit if the reference cell does not need to be programmed, e) performing steps a)-d) for a desired address range in the array, f) performing steps a)-d) for a desired number of reference cells, g) setting a sticky bit of the sticky bit buffer to a first logical state if one of the buffer bits indicates that one of the reference cells must be programmed, and if none of the buffer bits indicates that one of the reference cells must be programmed, then not changing a logical state of the sticky bit, h) reading the sticky bit, and i) applying a program pulse to the reference cell whose corresponding sticky bit is set to the first logical state.

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First Claim