Self-learning built-in self-test (bist) for leak detection in non-volatile memory

Abstract

In a word line leakage detection process in a NAND or other non-volatile memory device, to determine leaky blocks of a memory device, a reference value for block is determined by comparing the current drawn by the peripheral circuitry of the block with a sequence of comparison current values, corresponding to a range of digital values, while the peripheral circuit is not connected to the block. The current drawn when the peripheral circuitry is connected to the block is then determined, again by comparison with a sequence of comparison values, but of a reduced range of digital values, running from an offset above the reference value to an offset below the reference value. To further reduce test times, the same reference value is used for a group of blocks, such as groups of blocks that share a set of supply lines.