Fast programming of magnetic random access memory (MRAM)
A method of programming an MTJ includes selecting an MTJ that is coupled to an access transistor at the drain of the access transistor. The gate of the access transistor is coupled to a selected word line (WL), the selected WL being substantially at a first voltage, Vdd; whereas the WLs that are not coupled to the MTJ are left to float. A second voltage, Vx, is applied to the unselected bit lines (BLs) and further applied to a source line (SL), the SL being coupled to the source of the access transistor. A third voltage, Vdd or 0 Volts, is applied to a selected BL, the selected BL being coupled the MTJ. The first voltage is applied to a SL, the SL being coupled to the source of the access transistor thereby causing the WL to boot above the first voltage.
1. A method of programming a magnetoresistive tunnel junction (MTJ) coupled to a transistor, the transistor having a gate, a source, and a drain, the method comprising:
booting the voltage of a word line (WL) to a voltage substantially of Vddx volts, Vddx being substantially the sum of Vdd voltage and Vx voltage, the Vx voltage being greater than 0 volts and less than Vdd volts;
setting the voltage of a bit line (BL) to substantially the Vdd volts, the BL coupled to an end of the MTJ, the drain of the access transistor being coupled to an opposite end of the MTJ, a source line (SL) coupled to the source of the access transistor;
raising the SL to be substantially at Vx volts; and
programming the MTJ to a parallel state.
2. The method of programming, as recited in claim 1 , further including increasing the speed of programming by raising the voltage of the SL to Vx volts.
3. The method of programming, as recited in claim 1 , wherein the resistive element includes an MTJ.