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US 8,553,481 B2Granted
Sense amplifier latch with integrated test data multiplexer
AssigneeApple Inc.
InventorDaniel C. Chow
Life of this patent
Estimating the term…
Abstract
A sense amplifier latch may be provided to controllably latch the output of a sense amplifier. The latch may open in response to assertion of a latch enable signal to receive data, and close in response to deassertion of the latch enable signal to capture and store the received data. Additionally, a multiplexer may be provided to select from among multiple sources of test data, such as scan data and bypass data. The multiplexer may produce a test data input to the sense amplifier latch that encodes a data value and a control value that causes the data value to be selected. Depending on the state of the test data input, the sense amplifier latch may output either a value received from the sense amplifier or a value encoded in the test data input.
Claims20
An apparatus, comprising:
- a sense amplifier latch including a latch input, a test data input, a latch output, and a latch enable signal, wherein the latch input is coupled to receive one or more data output signals from a sense amplifier, wherein during operation, in response to assertion of the latch enable signal, the sense amplifier latch opens to pass a value of the latch input to the latch output, and in response to deassertion of the latch enable signal, the sense amplifier latch closes to store the value of the latch input;
- and
- a multiplexer that, during operation, selects one of a bypass input or a scan data input to generate the test data input, wherein the test data input encodes both a data value and a control value that causes the data value to be selected, and wherein in response to an indication by the control value of the test data output, the sense amplifier latch during operation overrides a stored data value with the data value encoded by the test data output, such that the sense amplifier latch outputs the data value received from the multiplexer instead of the stored data value.
A memory array, comprising:
- a plurality of storage cells arranged as a plurality of rows and a plurality of columns;
- a plurality of bit lines, including at least one respective bit line for each of the plurality of columns, wherein ones of the storage cells that occupy a given one of the columns are coupled to the at least one respective bit line corresponding to the given column;
- a plurality of sense amplifiers, including a respective sense amplifier for each of the plurality of columns, wherein the at least one respective bit line corresponding to the given column is coupled to the respective sense amplifier corresponding to the given column;
- a plurality of sense amplifier latches, including a respective sense amplifier latch for each of the plurality of columns, wherein a data output of the respective sense amplifier corresponding to the given column is coupled to and is controllably stored by the respective sense amplifier latch corresponding to the given column;
- a plurality of multiplexers, including a respective multiplexer for each of the plurality of columns, wherein a test data input of the respective sense amplifier latch corresponding to the given column is coupled to the respective multiplexer corresponding to the given column;
- wherein in response to assertion of a test enable signal, the respective multiplexer corresponding to the given column selects one of a bypass input or a scan data input to generate the test data input of the respective sense amplifier latch corresponding to the given column, wherein the test data input encodes both a data value and a control value that causes the data value to be selected;
- wherein in response to the control value of the test data output, the respective sense amplifier latch corresponding to the given column overrides a stored data value with the data value encoded by the test data input, such that the respective sense amplifier latch corresponding to the given column outputs the data value received from the multiplexer instead of the stored data value.
4 more elements
An apparatus, comprising:
- a multiplexer that, during operation, selects one of a bypass input or a scan data input to generate a test data output, wherein the test data output encodes both a test data value and a control value that causes the test data value to be selected;
- and
- a sense amplifier latch coupled to receive the test data output;
- wherein during operation, the sense amplifier latch controllably stores a data value received from a sense amplifier;
- wherein in response to an indication by the control value of the test data output that the test data value should be selected, the sense amplifier latch during operation outputs the test data value received from the multiplexer instead of the stored data value.
2 more elements
A method, comprising:
- storing a data value received from a sense amplifier on a storage node of a sense amplifier latch;
- evaluating a test data input of the sense amplifier latch, wherein the test data input encodes a control value and a test data value, wherein the control value is indicative of whether the test data value should be selected;
- and
- in response to determining that the control value indicates that the data value should be selected, outputting the data value from the sense amplifier latch instead of the value of the storage node.
1 more element
A microprocessor, comprising:
- an instruction execution core that, during operation, executes instructions;
- and
- one or more memory arrays that, during operation, store instructions, data operated on during execution of instructions, or state information used during execution of instructions;
- wherein the one or more memory arrays comprise:
- a multiplexer that, during operation, selects one of a bypass input or a scan data input to generate a test data output, wherein the test data output encodes both a test data value and a control value that causes the test data value to be selected;
- and
- a sense amplifier latch coupled to receive the test data output;
- wherein during operation, the sense amplifier latch controllably stores a data value received from a sense amplifier;
- wherein in response to an indication by the control value of the test data output that the test data value should be selected, the sense amplifier latch during operation outputs the test data value received from the multiplexer instead of the stored data value.
6 more elements
Dependencies are inferred from the claim text.