Method of writing to a spin torque magnetic random access memory
AssigneeEverspin Technologies, Inc.
InventorDimitri Houssameddine
Life of this patent
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Abstract
A method for determining an optimized write pattern for low write error rate operation of a spin torque magnetic random access memory. The method provides a way to optimize the write error rate without affecting the memory speed. The method comprises one or more write pulses. The pulses may be independent in amplitude, duration and shape. Various exemplary embodiments adjust the write pattern based on the memory operating conditions, for example, operating temperature.
Claims25
A method of determining a write pattern for writing to a plurality of bits in a spin-torque magnetoresistive memory array, the method comprising:
- determining a write voltage in accordance with design requirements for the array;
- determining the number of write pulses required for a predetermined write time and for minimizing a write error rate for the number of bits, wherein the number of write pulses is at least one;
- and
- applying the determined number of write pulses to the array.
A method of determining a write pattern for writing to a plurality of bits in a spin-torque magnetoresistive memory array, the method comprising:
- a) setting a write voltage Vw to a minimum voltage Vmin;
- b) setting a number of write pulses i to one and a write pulse duration t to a maximum duration Tmax;
- c) defining a write pattern as a single pulse of duration t with an amplitude Vw;
- d) characterizing a write error rate (WER) for the write pattern;
- e) defining write pulse settings as Vw, i, t and d if WER is less than a desired write error rate WER0;
- if WER is not less than WER0,
- f) setting i to i+1;
- g) setting the pulse duration t to (Tmax−(i−1)d)/i;
- and
- h) defining the write pattern as i pulses of duration t spaced by distance d with amplitude Vw;
- i) returning to the step d if t is not less than a minimum duration Tmin;
- and
- j) if t is less than Tmin, increasing Vw if Vw is not greater than or equal to a maximum voltage Vmax and returning to step b.
A system for determining a write pattern for writing to a spin-torque magnetoresistive memory array, the system comprising:
- a processor configured to:
- determine a write voltage in accordance with design requirements for the array;
- determine the number of write pulses required for a predetermined write time and for minimizing the WER for the number of bits, wherein the number of write pulses is at least one;
- and
- apply the determined number of write pulses to the array;
- and
- a plurality of bits in the array configured to:
- receive the determined number of write pulses.
Dependencies are inferred from the claim text.