Abstract: A scheme for PLL-based at-speed scan testing in which a clock generation circuit is used to generate different clock signals to scannable flip-flops of an integrated circuit. When the integrated circuit is under at-speed scan test mode of operation, the clock generation circuit receives a scan-clock signal to scan in a test vector to the scannable flip-flops during an input shift phase when shifting is enabled and to scan out a resultant vector from the scannable flip-flops during an output shift phase when shifting is also enabled. However, when shifting is not enabled during a capture phase between the two shift phases, the scan-clock signal triggers a 2-pulse circuit to release two pulses during the capture phase of at-speed scan testing. The two pulses from the 2-pulse circuit are based on an internal PLL-based clock signal. The clock generation circuit may be utilized in single or multiple clock domain systems.

Abstract: An improved automated testing system that decreases the number of test signals that must be stored in the tester pattern memory for a timed test pattern. In the present invention, a timed test pattern is controlled by a timing generator operable to change the timing interval of individual test cycles during the timed test pattern between first and second timing intervals, thereby decreasing the number of test signals stored in pattern memory for the timed test pattern. The method and apparatus of the present invention can be implemented to test integrated circuits comprising circuitry operating in first and second time domains wherein the first and second timing intervals of the timed test pattern correspond to the first and second time domains of the circuit, respectively.

Abstract: A scheme for PLL-based at-speed scan testing in which a clock generation circuit is used to generate different clock signals to scannable flip-flops of an integrated circuit. When the integrated circuit is under at-speed scan test mode of operation, the clock generation circuit receives a scan-clock signal to scan in a test vector to the scannable flip-flops during an input shift phase when shifting is enabled and to scan out a resultant vector from the scannable flip-flops during an output shift phase when shifting is also enabled. However, when shifting is not enabled during a capture phase between the two shift phases, the scan-clock signal triggers a 2-pulse circuit to release two pulses during the capture phase of at-speed scan testing. The two pulses from the 2-pulse circuit are based on an internal PLL-based clock signal. The clock generation circuit may be utilized in single or multiple clock domain systems.

Abstract: In one embodiment, a clock multiplier circuit is coupled to receive an input signal and is configured to generate an output clock signal. The clock multiplier circuit is configured to generate a number of pulses on the output clock signal responsive to an edge of the input signal, wherein the pulses have a width that is independent of the number of pulses generated and independent of the frequency of the input signal. The number of pulses is selectable. In another embodiment, the clock multiplier circuit includes a circuit and an oscillator. The circuit is configured to cause a number of pulses on the output clock signal of the clock multiplier circuit responsive to a control signal. The oscillator is configured to generate a stream pulses having the width, wherein the circuit is coupled to receive the stream of pulses.

Abstract: A method for locating a repair solution for a memory that includes a memory array comprising a plurality of rows and a plurality of columns, N redundant rows, and M redundant columns is described. Both N and M are integers, where N is greater than or equal to zero and M is greater than or equal to zero. The N redundant rows and the M redundant columns are collectively referred to as redundant lines. The method includes generating a first defect matrix representing defects in the memory array. Additionally, the method includes recursively, until either the repair solution is found or the redundant lines are consumed: selecting a first line represented in the defect matrix and having at least one defect; generating a second defect matrix by eliminating at least the defects in the first line from the first defect matrix; and determining if the repair solution is found.

Abstract: An improved automated testing system that decreases the number of test signals that must be stored in the tester pattern memory for a timed test pattern. In the present invention, a timed test pattern is controlled by a timing generator operable to change the timing interval of individual test cycles during the timed test pattern between first and second timing intervals, thereby decreasing the number of test signals stored in pattern memory for the timed test pattern. The method and apparatus of the present invention can be implemented to test integrated circuits comprising circuitry operating in first and second time domains wherein the first and second timing intervals of the timed test pattern correspond to the first and second time domains of the circuit, respectively.

Abstract: A clock multiplier circuit receives a clock input signal and generates a clock output signal. The clock multiplier circuit generates a number of pulses to be used as the clock output signal, wherein the pulses have a pulsewidth that is independent of the number of pulses generated and independent of the frequency of the clock input signal. The clock multiplier circuit includes an oscillator and a logic circuit which generates a control signal for synchronization of the pulses to the control signal and to mask the pulses after a selected number of pulses have been output as the clock output signal. The clock multiplier circuit causes a number of unmasked pulses to be output as the clock output signal in response to the control signal, while other pulses are masked.

Abstract: A method for locating a repair solution for a memory that includes a memory array comprising a plurality of rows and a plurality of columns, N redundant rows, and M redundant columns is described. Both N and M are integers, where N is greater than or equal to zero and M is greater than or equal to zero. The N redundant rows and the M redundant columns are collectively referred to as redundant lines. The method includes generating a first defect matrix representing defects in the memory array. Additionally, the method includes recursively, until either the repair solution is found or the redundant lines are consumed: selecting a first line represented in the defect matrix and having at least one defect; generating a second defect matrix by eliminating at least the defects in the first line from the first defect matrix; and determining if the repair solution is found.

Abstract: In one embodiment, a clock multiplier circuit is coupled to receive an input signal and is configured to generate an output clock signal. The clock multiplier circuit is configured to generate a number of pulses on the output clock signal responsive to an edge of the input signal, wherein the pulses have a width that is independent of the number of pulses generated and independent of the frequency of the input signal. The number of pulses is selectable. In another embodiment, the clock multiplier circuit includes a circuit and an oscillator. The circuit is configured to cause a number of pulses on the output clock signal of the clock multiplier circuit responsive to a control signal. The oscillator is configured to generate a stream pulses having the width, wherein the circuit is coupled to receive the stream of pulses.

Abstract: A method for locating a repair solution for a memory that includes a memory array containing a plurality of rows and a plurality of columns, N redundant rows, and M redundant columns. Both N and M are integers, where N is greater than or equal to zero and M is greater than or equal to zero. The N redundant rows and the M redundant columns are collectively referred to as redundant lines. The method includes generating a first defect matrix defects in the memory array. Additionally, the method includes recursively, until either the repair solution is found or the redundant lines are consumed: selecting a first line in the defect matrix and having at least one defect; generating a second defect matrix by eliminating at least the defects in the first line from the first defect matrix; and determining if the repair solution is found.

Abstract: A clock multiplier circuit is receives an input signal and generates a clock output signal. The clock multiplier circuit generates a number of pulses to be used as the clock output signal, wherein the pulses have a pulsewidth that is independent of the number of pulses generated and independent of the frequency of a clock control signal used for masking. The clock multiplier circuit includes an oscillator, a storage device for synchronization of the masking signal to the pulses and a logic circuit to generate the clock output signal. The clock multiplier circuit causes a number of unmasked pulses to be output as the output clock signal in response to the clock control signal, while other pulses are masked.

Abstract: In one embodiment, a clock multiplier circuit is coupled to receive an input signal and is configured to generate an output clock signal. The clock multiplier circuit is configured to generate a number of pulses on the output clock signal responsive to an edge of the input signal, wherein the pulses have a width that is independent of the number of pulses generated and independent of the frequency of the input signal. The number of pulses is selectable. In another embodiment, the clock multiplier circuit includes a circuit and an oscillator. The circuit is configured to cause a number of pulses on the output clock signal of the clock multiplier circuit responsive to a control signal. The oscillator is configured to generate a stream pulses having the width, wherein the circuit is coupled to receive the stream of pulses.

Abstract: An integrated circuit is provided with Fully Automated Scan Testing (FAST)-lite flip-flop. The integrated circuit has data, scan in, master-hold, clock, scan-into-master, and master to-scan-out inputs. A first transistor circuit is connected to the data, master-hold, and clock inputs and has a first transistor circuit output. A second transistor circuit is connected to the can in and scan-into-master inputs and has a second transistor circuit output. A first flip-flop is connected to the first transistor circuit and second transistor circuit outputs and has a first flip-flop output. A third transistor circuit is connected to the second transistor circuit output and the master-to-scan-out input and has a third transistor circuit output. A second flip-flop latch is connected to the third transistor circuit output has a second flip-flop output. The FAST-lite flip-flop uses the normal functionality of the first flip-flop and second flip-flop to operate either in a normal mode or a test mode for scan testing.

Abstract: A method of detecting open circuit defects within an integrated circuit. The invention includes locating a conductive plate proximate to a top surface of the integrated circuit. A voltage potential is coupled to the conductive plate. The voltage potential of the conductive plate couples to open circuit interconnections within the integrated circuit. Open circuit interconnections are identified by monitoring the quiescent current conducted by the integrated circuit while controlling the voltage on the conductive plate and controlling inputs to the integrated circuit.

Abstract: A test vector system (157) and method for generating and verifying test vectors for testing integrated circuit speed paths involves accessing a circuit model (160), a list of circuit paths (162) and a test vector verifier (165). A single circuit path, referred to as a selected path, is selected from the paths (162). Once logical constraints are set, hazard-free logical values and logical values for both the second test clock cycle and the first test clock cycle are justified. Test vectors are generated in response to the justified values and the test vectors are used as input to the test vector verifier. The test verifier produces patterns that provide robust delay path fault tests for the given path. The test patterns are serially shifted and double-clocked in an integrated circuit or electrical circuit manufactured in accordance with circuit model (160) to determine time delay path faults.

Abstract: A test vector generator system (157) and method for generating test vectors for testing integrated circuit speed paths involves accessing both a circuit model (160) and a list of circuit paths (162). A single circuit path, referred to as a selected path, is selected from the paths (162), and a set of logic value constraints are set for logic devices in the selected circuit path. These logical constraints are set to ensure that a proper input-to-output transition, which is used to identify speed path faults, results in response to only two clock cycles. Once logical constraints are set, hazard-free logical values and logical values for both the second test clock cycle and the first test clock cycle are justified. Test vectors are generated in response to the justified values and the test vectors are serially shifted and double-clocked in an integrated circuit or electrical circuit manufactured in accordance with circuit model (160) to determine time delay path faults.

Abstract: A test vector generator system (157) and method for generating test vectors for testing integrated circuit speed paths involves accessing both a circuit model (160) and a list of circuit paths (162). A single circuit path, referred to as a selected path, is selected from the paths (162). A set of logic value constraints is set for custom logic blocks, through the use of Boolean differences, and a set of logic value constraints is set for standard logic devices in the selected circuit path. These logical constraints are set to ensure that a proper input-to-output transition, which is used to identify speed path faults, results in response to only two clock cycles. Once logical constraints are set, hazard-free logical values and logical values for both the second test clock cycle and the first test clock cycle are justified.