Writing Circuitry for Toggle MRAM to Screen Intermittent Failure Mode

Takeshi HONDA  Noboru SAKIMURA  Tadahiko SUGIBAYASHI  Naoki KASAI  Hiromitsu HADA  Shu-ichi TAHARA  

IEICE TRANSACTIONS on Electronics   Vol.E90-C   No.2   pp.531-535
Publication Date: 2007/02/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e90-c.2.531
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Integrated Electronics
MRAM,  toggle,  intermittent failure,  

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We propose a writing circuit scheme to screen intermittent failure cells for toggle MRAM. The scheme, comprising a current waveform circuitry that controls rise/fall time of writing current, drastically decreases the probability of intermittent failure. To apply the scheme to large-capacity MRAMs, a current booster containing discharging capacitors has also been developed. It adjusts the waveform of writing current to that designed by the current waveform circuitry even in presence of parasitic capacitors and resistors along the writing current path. Such a technique is essential for achieving stability in large-capacity MRAMs.