Configurable MRAM and method of configuration
View Patent ↗A configurable MRAM device is achieved. The device comprises a memory array of magnetic memory cells. A first part of the array comprises the memory cells that can be accessed for reading and writing during normal operation. A second part of the array comprises the memory cells that can be read only during a power up initialization. The second part of the array is used to store configuration data for altering the physical operation of the memory array. Programmable current sources and timing delays use the stored configuration data to optimize device performance. A redundant section of memory cells is activated by the configuration data.
1. A configurable MRAM device comprising an array of magnetic memory cells wherein a first part of said array comprises said memory cells that can be accessed for reading and writing during normal operation, wherein a second part of said array comprises said memory cells that can be read only during a power up initialization, and wherein said second part of said array is used to store configuration data for altering the physical operation of said array.
2. The device according to claim 1 further comprising a programmable current source wherein the performance of said programmable current source is governed by said configuration data.
3. The device according to claim 2 wherein said programmable current source provides bit line current for reading a magnetic memory cell.
4. The device according to claim 2 wherein said programmable current source provides bit line current for writing a magnetic memory cell.
5. The device according to claim 2 wherein said programmable current source provides word line current for writing a magnetic memory cell.
6. The device according to claim 2 wherein performance of said programmable current source is governed by an external input to said device when said device is in test mode.
7. The device according to claim 1 further comprising a programmable timing controller wherein the performance of said programmable timing controller is governed by said configuration data.
8. The device according to claim 7 wherein said programmable timing controller provides a delay time between delivering word line current and delivering bit line current to said magnetic memory cells during a writing operation.
9. The device according to claim 7 wherein said programmable timing controller controls the timing of latching data sensed from said array during a reading operation.
10. The device according to claim 7 wherein performance of said programmable timing controller is governed by an external input to said device when said device is in test mode.
11. The device according to claim 1 further comprising a third part of said array comprising said memory cells that can be accessed for reading and writing in normal operation only as redundant cells that are activated when said memory cells of said first part of array are identified as defective by said configuration data.
12. The device according to claim 11 wherein said configuration data is read during power up initialization by a method comprising:
reading a fixed number of bytes to determine how many defective cell addresses have been replaced by redundant cell addresses; and
reading out all of said defective cell addresses.
13. The device according to claim 11 wherein a normal row in said first part of said array is disabled when a redundant row in said third part of said array is enabled.
14. The device according to claim 1 wherein a second array of said magnetic memory cells provides bit line reference values for reading operations.
15. A configurable MRAM device comprising:
an array of magnetic memory cells wherein a first part of said array comprises said memory cells that can be accessed for reading and writing during normal operation, wherein a second part of said array comprises said memory cells that can be read only during a power up initialization, wherein said second part of said array is used to store configuration data for altering the physical operation of said array; and
a programmable current source wherein the performance of said programmable current source is governed by said configuration data.
16. The device according to claim 15 wherein said programmable current source provides bit line current for reading a magnetic memory cell.
17. The device according to claim 15 wherein said programmable current source provides bit line current for writing a magnetic memory cell.
18. The device according to claim 15 wherein said programmable current source provides word line current for writing a magnetic memory cell.
19. The device according to claim 15 wherein performance of said programmable current source is governed by an external input to said device when said device is in test mode.
20. The device according to claim 15 further comprising a programmable timing controller wherein the performance of said programmable timing controller is governed by said configuration data.
21. The device according to claim 20 wherein said programmable timing controller provides a delay time between delivering word line current and delivering bit line current to said magnetic memory cells during a writing operation.
22. The device according to claim 21 wherein said programmable timing controller controls the timing of latching data sensed from said array during a reading operation.
23. The device according to claim 21 wherein performance of said programmable timing controller is governed by an external input to said device when said device is in test mode.
24. The device according to claim 15 further comprising a third part of said array comprising said memory cells that can be accessed for reading and writing in normal operation only as redundant cells that are activated when said memory cells of said first part of array are identified as defective by said configuration data.
25. The device according to claim 24 wherein said configuration data is read during power up initialization by a method comprising:
reading a fixed number of bytes of said configuration data to determine the number of cell addresses that have been replaced by redundant cell addresses; and
thereafter reading out all of said defective cell addresses of said configuration data.
26. The device according to claim 24 wherein a normal row in said first part of memory array is disabled when a redundant row in said third part of memory array is enabled.
27. The device according to claim 15 wherein a second array of said magnetic memory cells provides bit line reference values for reading operations.
28. A method to configure a MRAM device, said device comprising an array of magnetic memory cells wherein a first part of said array comprises said memory cells that can be accessed for reading and writing during normal operation, wherein a second part of said array comprises said memory cells that can be read only during a power up initialization, and wherein said second part of said array is used to store configuration data for altering the physical operation of said array, and said method comprising:
storing said configuration data in said second part of array;
thereafter generating a power-up initialization for said device;
thereafter reading a fixed number of bytes to latch settings for said physical operation of said array and to determine the number of variable configuration data rows;
thereafter reading out all of said variable configuration data rows; and
thereafter ending said power-up initialization.
29. The method according to claim 28 wherein said device further comprises a programmable current source wherein the performance of said programmable current source is governed by said configuration data.
30. The method according to claim 29 further comprising testing the performance of said programmable current source by controlling said programmable current source via an external input to said device in test mode prior to said step of storing said configuration data in said second part of array.
31. The method according to claim 29 wherein said device further comprises a programmable timing controller wherein the performance of said programmable timing controller is governed by said configuration data.
32. The method according to claim 31 further comprising testing the performance of said programmable timing controller by controlling said programmable timing controller via an external input to said device in test mode prior to said step of storing said configuration data in said second part of array.
33. The method according to claim 28 wherein said device further comprises a third part of said array comprising said memory cells that can be accessed for reading and writing in normal operation only as redundant cells that are activated when said memory cells of said first part of array are identified as defective by said configuration data.