Integrated circuit with sensing unit and method for using the same

1. A circuit comprising:

a first conductor;

a second conductor;

a magnetic memory circuit including a magnetic storage element disposed between the said first and second conductors, wherein the magnetic storage element comprises a magnetic tunnel junction (MTJ) stack;

a sensing circuit configured to determine a change in conductivity of the magnetic storage element by monitoring a voltage drop across the magnetic storage element when a constant current is passed from the first conductor to the second conductor, thereby passing through the magnetic storage element; and

an indicator configured to indicate that the magnetic storage element is not reliable for use when the change in conductivity exceeds a pre-determined value.

2. The circuit of claim 1 , wherein the indicator comprises at least one of an audio indicator or a visual indicator.

3. The circuit of claim 1 , wherein the magnetic storage element is configured to not contain any stored data when the sensing circuit monitors the voltage drop across the magnetic storage element.

4. A method of using a circuit, the method comprising:

using a sensing unit in the circuit, wherein the sensing unit comprises a magnetic memory circuit including a magnetic storage element, two conductors, and a sensing circuit, and wherein the magnetic storage element comprises a magnetic tunnel junction (MTJ) stack;

determining, by the sensing circuit, a change in conductivity of the magnetic storage element by monitoring a voltage drop across the magnetic storage element when a constant current is passed from a first of the two conductors to a second of the two conductors, thereby passing through the magnetic storage element; and

indicating, by an indicator, that the magnetic storage element is not reliable for use when the change in conductivity exceeds a pre-determined value.

5. The method of claim 4 , wherein the indicator comprises at least one of an audio indicator or a video indicator.

6. The method of claim 4 , wherein the magnetic storage element does not contain any stored data when the sensing circuit monitors the voltage drop across the magnetic storage element.

7. A method of using a circuit, the method comprising:

using a plurality of sensing units in the circuit, wherein each of the plurality of sensing units comprises a magnetic memory circuit including a magnetic storage element, two conductors, and a sensing circuit, and wherein the magnetic storage element comprises a magnetic tunnel junction (MTJ) stack;

in each of the plurality of sensing units, determining, by the sensing circuit, a change in conductivity of the magnetic storage element by monitoring a voltage drop across the magnetic storage element by said sensing circuit when a constant current is passed from a first of the two conductors to a second of the two conductors, thereby passing through the magnetic storage element; and

indicating, by an indicator, that the plurality of magnetic storage elements is not reliable for use when the change in conductivity exceeds a pre-determined value.

8. The method of claim 7 , further comprising:

operating the sensing units by a multiplexer that is disposed in the circuit.

9. The method of claim 7 , wherein each of the plurality of magnetic storage elements has a different aspect ratio for indicating the change in conductivity with improved sensitivity when the change in conductivity in the magnetic storage element is caused by a magnetic field from a particular direction.

10. The method of claim 7 , wherein a selected magnetic storage element is storing no data when a sensing unit is monitoring a voltage drop across the selected magnetic storage element.

11. A circuit comprising:

a first conductor;

a second conductor;

a magnetic memory circuit including a magnetic storage element comprising a magnetic tunnel junction (MTJ) stack including:

a fixed layer electrically connected to the first conductor;

a tunnel oxide layer above the fixed layer; and

a free layer above the tunnel oxide layer, wherein the second conductor is electrically connected to the free layer;

at least one constant current source configured to drive a constant current from the first conductor to the second conductor, thereby passing through the magnetic storage element;

sensing circuitry configured to measure the conductivity of the magnetic storage element while the constant current is driven from the first conductor to the second conductor; and

an indicator configured to indicate that the magnetic storage element is not reliable for use when a change in conductivity exceeds a pre-determined value.

12. A circuit comprising:

a plurality of first conductors;

a plurality of second conductors;

a plurality of magnetic memory circuits including a corresponding plurality of magnetic storage elements, wherein each of the plurality of magnetic storage elements includes a fixed layer electrically connected to one of the plurality of first conductors, and wherein each of the plurality of magnetic storage elements includes a free layer electrically connected to one of the plurality of second conductors, and wherein each of the plurality of magnetic storage elements comprises a magnetic tunnel junction (MTJ) stack;

a plurality of sensing circuitries corresponding to the plurality of magnetic storage elements;

wherein:

at least one constant current source is configured to drive constant currents from each of the first conductors to a respective one of each of the second conductors, thereby passing through a respective one of the plurality of magnetic storage elements; and

the plurality of sensing circuitries is configured to measure a change in conductivity in the plurality of magnetic storage elements if the constant currents are passed through the plurality of magnetic storage elements; and

an indicator configured to indicate that the plurality of magnetic storage elements is not reliable for use when the change in conductivity exceeds a pre-determined value.

13. The circuit of claim 12 , wherein each of the plurality of magnetic storage elements comprises a different aspect ratio.