Abstract: An integrated circuit comprises a decoder having a plurality of select signal outputs, a multiplexer having a plurality of select signal inputs subject to a specified select signal constraint, and scan test circuitry. The scan test circuitry comprises at least one scan chain having a plurality of scan cells coupled between respective ones of the select signal outputs of the decoder and respective ones of the select signal inputs of the multiplexer. The scan test circuitry is configured to control at least a given one of the scan cells so as to prevent violation of the select signal constraint in conjunction with scan testing. The multiplexer may be, for example, a one-hot multiplexer for which the select signal constraint indicates that only one of the select signal inputs should receive a logic high select signal at a particular time.

Abstract: An integrated circuit comprises a decoder having a plurality of select signal outputs, a multiplexer having a plurality of select signal inputs subject to a specified select signal constraint, and scan test circuitry. The scan test circuitry comprises at least one scan chain having a plurality of scan cells coupled between respective ones of the select signal outputs of the decoder and respective ones of the select signal inputs of the multiplexer. The scan test circuitry is configured to control at least a given one of the scan cells so as to prevent violation of the select signal constraint in conjunction with scan testing. The multiplexer may be, for example, a one-hot multiplexer for which the select signal constraint indicates that only one of the select signal inputs should receive a logic high select signal at a particular time.

Abstract: An apparatus having a core and one or more logic blocks is disclosed. The core may be embedded within the apparatus. The core is generally (i) configured to perform a function and (ii) wrapped internally by a first scan chain before being embedded within the apparatus. The logic blocks may be (i) positioned external to the core and (ii) coupled to one or more parallel interfaces of the first scan chain. A second scan chain may be configured to wrap both the logic blocks and the core.

Abstract: An apparatus having a core and one or more logic blocks is disclosed. The core may be embedded within the apparatus. The core is generally (i) configured to perform a function and (ii) wrapped internally by a first scan chain before being embedded within the apparatus. The logic blocks may be (i) positioned external to the core and (ii) coupled to one or more parallel interfaces of the first scan chain. A second scan chain may be configured to wrap both the logic blocks and the core.

Abstract: A method and an apparatus for evaluating SDDC of a test pattern set are disclosed. In one embodiment, the method includes: (1) selecting a transition fault of an IC detected by a test pattern set, the transition fault occurring at a fault site of the IC, (2) identifying path delays of a longest testable path and a longest tested path of the IC, wherein both the longest testable path and the longest tested path include the fault site, (3) determining a SDD detection probability for both the longest testable path and the longest tested path based on a probability that a SDD will be detected if present at the fault site and (4) calculating SDDC for the transition fault by dividing the SDD detection probability of the longest tested path by the SDD detection probability of the longest testable path.

Abstract: Clock control circuitry for an integrated circuit, a method of testing an integrated circuit having a clock gate, an integrated circuit and a library of cells including the clock control circuitry are provided. In one embodiment, the integrated circuit includes: (1) a clock gate configured to apply a clock signal to at least a first scan chain of the integrated circuit, (2) combinational logic coupled to an input of the clock gate and (3) Design-for-Test logic located external to the combinational logic and coupled to the clock gate and a first cell of a second scan chain of the integrated circuit, the Design-for-Test logic configured to control operation of the clock gate based on a logic value of the first cell.

Abstract: A method for generating a test pattern set for detecting small delay defects of an IC is disclosed. In one embodiment, the method includes: (1) generating a traditional delay fault pattern, (2) fault grading the traditional delay fault pattern for small delay defect coverage, (3) reporting faults detected by the fault grading and delay information associated with the detected faults, (4) determining which of the detected faults are timing-aware target faults employing the delay information and (5) generating timing-aware delay fault patterns for the timing-aware target faults.

Abstract: Clock control circuitry for an integrated circuit, a method of testing an integrated circuit having a clock gate, an integrated circuit and a library of cells including the clock control circuitry are provided. In one embodiment, the integrated circuit includes: (1) a clock gate configured to apply a clock signal to at least a first scan chain of the integrated circuit, (2) combinational logic coupled to an input of the clock gate and (3) Design-for-Test logic located external to the combinational logic and coupled to the clock gate and a first cell of a second scan chain of the integrated circuit, the Design-for-Test logic configured to control operation of the clock gate based on a logic value of the first cell.

Abstract: The disclosure provides embodiments of ICs and a method of testing an IC. In one embodiment, an IC includes: (1) a functional logic path having a node and at least one sequential logic element and (2) test circuitry coupled to the functional logic path and having a delay block, the test circuitry configured to form a testable path including the delay block and the node in response to a test mode signal, wherein a delay value of the delay block is selected to detect a small delay defect associated with the node.

Abstract: The disclosure provides embodiments of ICs and a method of testing an IC. In one embodiment, an IC includes: (1) a functional logic path having a node and at least one sequential logic element and (2) test circuitry coupled to the functional logic path and having a delay block, the test circuitry configured to form a testable path including the delay block and the node in response to a test mode signal, wherein a delay value of the delay block is selected to detect a small delay defect associated with the node.

Abstract: A method and an apparatus for evaluating SDDC of a test pattern set are disclosed. In one embodiment, the method includes: (1) selecting a transition fault of an IC detected by a test pattern set, the transition fault occurring at a fault site of the IC, (2) identifying path delays of a longest testable path and a longest tested path of the IC, wherein both the longest testable path and the longest tested path include the fault site, (3) determining a SDD detection probability for both the longest testable path and the longest tested path based on a probability that a SDD will be detected if present at the fault site and (4) calculating SDDC for the transition fault by dividing the SDD detection probability of the longest tested path by the SDD detection probability of the longest testable path.

Abstract: A method for generating a test pattern set for detecting small delay defects of an IC is disclosed. In one embodiment, the method includes: (1) generating a traditional delay fault pattern, (2) fault grading the traditional delay fault pattern for small delay defect coverage, (3) reporting faults detected by the fault grading and delay information associated with the detected faults, (4) determining which of the detected faults are timing-aware target faults employing the delay information and (5) generating timing-aware delay fault patterns for the timing-aware target faults.