Nonvolatile CMOS latch employing GMR resistors

A nonvolatile latch has been demonstrated using Giant-Magneto-Resistance (GMR) thin film resistors placed atop a conventional .35µm bulk CMOS process. The latch employs two GMR resistors that are programmed in complementary states by a pulse of 20- 50mA current passing through metal lines placed immediately below the resistors. Sensing of the relative resistor values is accomplished via a cross-coupled inverter sense-amplifier that consumes zero quiescent power after regeneration and that may also be used as a conventional SRAM cell. Preliminary experimental results indicate that sensing may be accomplished in <40nsec. with a current during reading of about 420 µA. Total die size of the latch is about 248×57 sq. microns.