Sense amplifier offset voltage reduction

Patent metadata

Field	Value
Publication number	US-9140747-B2
Application number	US-201313947144-A
Country	US
Kind code	B2
Filing date	Jul 22, 2013
Priority date	Jul 22, 2013
Publication date	Sep 22, 2015
Grant date	Sep 22, 2015

Abstract

A circuit includes a plurality of transistors responsive to a plurality of latches that store a test code. The circuit further includes a first bit line coupled to a data cell and coupled to a sense amplifier. The circuit also includes a second bit line coupled to a reference cell and coupled to the sense amplifier. A current from a set of the plurality of transistors is applied to the data cell via the first bit line. The set of the plurality of transistors is determined based on the test code. The circuit also includes a test mode reference circuit coupled to the first bit line and to the second bit line.

First claim

What is claimed is:

1. A circuit comprising:
a plurality of transistors responsive to a plurality of latches that store a test code;
a first bit line coupled to a data cell and coupled to a sense amplifier;
a second bit line coupled to a reference cell and coupled to the sense amplifier, wherein a current from a set of the plurality of transistors is applied to the data cell via the first bit line, and wherein the set of the plurality of transistors is determined based on the test code; and
a test mode reference circuit coupled to the first bit line and to the second bit line.

2. The circuit of claim 1 , wherein the test code comprises logic one values and logic zero values, and wherein each of the logic zero values triggers conduction of a transistor of the plurality of transistors.

3. The circuit of claim 1 , further comprising a test mode control circuit configured to provide a series of test codes to the plurality of latches to determine a characteristic of the sense amplifier.

4. The circuit of claim 3 , wherein the test mode control circuit determines an offset compensation code, wherein the offset compensation code corresponds to a particular test code of the series of test codes, and wherein the particular test code causes the output of the sense amplifier to change a state.

5. The circuit of claim 3 , wherein the test mode reference circuit includes:
a first test mode resistor coupled to the first bit line via a first selection transistor; and
a second test mode resistor coupled to the second bit line via a second selection transistor, wherein the first test mode resistor and the second test mode resistor have substantially equal resistances;
wherein, during operation in a test mode, each test code of the series of test codes corresponds to a different current that is provided to the first test mode resistor.

6. The circuit of claim 5 , wherein the data cell and the reference cell are isolated from the sense amplifier during operation in the test mode.

7. The circuit of claim 5 , wherein the test code is determined based on an output of the sense amplifier during operation in the test mode.

8. The circuit of claim 1 , integrated in at least one semiconductor die.

9. The circuit of claim 1 , further comprising a device selected from the group consisting of a set top box, a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, and a computer, into which the sense amplifier is integrated.

10. The circuit of claim 1 , wherein the data cell is a memory cell within one of a magnetoresistive random access-memory (MRAM), a phase change random access memory (PRAM), a spin-transfer torque magnetoresistive random-access memory (STT-MRAM), a ferroelectric random-access memory (FRAM), or a resistive random-access memory (ReRAM).

11. A method comprising:
providing a test code to a plurality of latches that are coupled to a plurality of transistors; and
applying a current from a set of the plurality of transistors to a bit cell via a first bit line, wherein the set of the plurality of transistors is determined based on the test code, and wherein the test code is determined based on an output of a sense amplifier provided during operation of the sense amplifier in a test mode.

12. The method of claim 11 , wherein the test code is provided to the plurality of latches by serially shifting the test coded into the plurality of latches.

13. The method of claim 11 , wherein an offset compensation code is determined, during operation in the test mode, by sweeping through a plurality of test codes and monitoring the output of the sense amplifier.

14. The method of claim 13 , further comprising storing the offset compensation code in the plurality of latches.

15. The method of claim 13 , further comprising:
storing the offset compensation code in a one-time programmable memory during operation in the test mode; and
transferring the offset compensation code to the plurality of latches during operation in a sensing mode.

16. The method of claim 13 , further comprising:
storing the offset compensation code in a magnetoresistive random-access memory (MRAM) cell array during operation in the test mode; and
transferring the offset compensation code to the plurality of latches during operation in a sensing mode.

17. The method of claim 11 , wherein providing the test code to the plurality of latches is performed by a processor integrated into an electronic device.

18. An apparatus comprising:
means for latching a test code; and
means for providing a current to a first bit line to read a bit cell via based on the test code, wherein the test code is determined based on an output of a sense amplifier provided during operation of the sense amplifier in a test mode.

19. The apparatus of claim 18 , further comprising means for providing the test code to the means for latching, wherein the test code is provided to the means for latching by serially shifting the test code into the means for latching.

20. The apparatus of claim 18 , further comprising a device selected from the group consisting of a set top box, a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, and a computer, into which the means for latching the test code and the means for providing the current are integrated.

21. A computer-readable storage medium comprising instructions that, when executed by a processor, cause the processor to:
provide a test code to a plurality of latches that are coupled to a plurality of transistors;
wherein a set of the plurality of transistors applies current via a first bit line to a bit cell in response to receiving signals from the plurality of latches based on the test code, wherein the set of the plurality of transistors is determined based on the test code, and wherein the test code is determined based on an output of a sense amplifier provided during operation of the sense amplifier in a test mode.

22. The computer-readable storage medium of claim 21 , wherein the test code is provided to the plurality of latches by serially shifting the test coded into the plurality of latches.

23. The computer-readable storage medium of claim 21 , wherein the processor is integrated into a device selected from the group consisting of a set top box, a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant (PDA), a fixed location data unit, and a computer.

24. A method comprising:
receiving design information representing at least one physical property of a semiconductor device, the semiconductor device comprising:
a plurality of transistors responsive to a plurality of latches that store a test code;
a first bit line coupled to a data cell and coupled to a sense amplifier;
a second bit line coupled to a reference cell and coupled to the sense amplifier, wherein a current from a set of the plurality of transistors is applied to the data cell via the first bit line, and wherein the set of the plurality of transistors is determined based on the test code; and
a test mode reference circuit coupled to the first bit line and to the second bit line;

transforming the design information to comply with a file format; and
generating a data file including the transformed design

Assignees

• Qualcomm Inc

Inventors

• Kim Jung Pill
• Kim Taehyun
• Kim Sungryul
• Kim Daeik D

Classifications

• G11C29/026 Primary

  in sense amplifiers · CPC title

• G11C29/46

  Test trigger logic · CPC title

• G11C29/14

  Implementation of control logic, e.g. test mode decoders · CPC title

• G11C29/44

  Indication or identification of errors, e.g. for repair · CPC title

• G01R31/2851 Primary

  Testing of integrated circuits [IC] (G01R31/317 takes precedence; testing individual devices G01R31/26; testing printed circuits G01R31/2801) · CPC title