A method of identifying cell-internal defects: obtaining a circuit design of an integrated circuit, the circuit design including netlists of one or more cells coupled to one another; identifying the netlist corresponding to one of the one or more cells; injecting a defect to one of a plurality of circuit elements and one or more interconnects of the cell; retrieving a first current waveform at a location of the cell where the defect is injected by applying excitations to inputs of the cell; retrieving, without the defect injected, a second current waveform at the location of the cell by applying the same excitations to the inputs of the cell; and selectively annotating, based on the first current waveform and the second current waveform, an input/output table of the cell with the defect.

A system includes a multiple input signature register (MISR) to receive outputs from M different scan chains in response to N test patterns applied to test an integrated circuit. The MISR provides N test signatures for the integrated circuit based on the outputs of the M different scan chains generated in response to each of the N test patterns. Each of the scan chains holds one or more test data bits that represent behavior of the integrated circuit in response to each of the N test patterns. A shift register is loaded from an interface and holds one of N comparison signatures that is used to validate a respective one of the N test signatures generated according to a given one of the N test patterns. A comparator compares each of the N test signatures with a respective one of the N comparison signatures to determine a failure condition based on the comparison.

The disclosure describes novel methods and apparatuses for accessing test compression architectures (TCA) in a device using either a parallel or serial access technique. The serial access technique may be controlled by a device tester or by a JTAG controller. Further the disclosure provides an approach to access the TCA of a device when the device exists in a daisy-chain arrangement with other devices, such as in a customer's system. Additional embodiments are also provided and described in the disclosure.

Embodiments herein relate to apparatus, systems, and methods to compress a test pattern onto a field programmable gate array to test a device under test. This may include identifying values of a plurality of drive pins for a plurality of test cycles to apply to an input of the DUT for each of the plurality of test cycles, identifying values of a plurality of compare pins for the plurality of test cycles to compare an output of the DUT, respectively, for each of the plurality of test cycles, analyzing the identified values, compressing, based on the analysis, the values of the plurality of drive pins and the plurality of compare pins, and storing the compressed values on the FPGA.

A system for testing a circuit comprises scan chains, a controller configured to generate a bit- inverting signal based on child test pattern information, and bit-inverting circuitry coupled to the controller and configured to invert bits of a parent test pattern associated with a plurality of shift clock cycles based on the bit-inverting signal to generate a child test pattern during a shift operation. Here, the plurality of shift clock cycles for bit inverting occur every m shift clock cycles, and the child test pattern information comprises information of m and location of the plurality of shift clock cycles in the shift operation.

A method includes executing a test against a first structure and a second structure of a built-in self-test circuit. Each of the first and second structures include a plurality of latches arranged as a plurality of stump chains. The method also includes unloading a first result of the test from the plurality of stump chains of the first structure and a second result of the test from the plurality of stump chains of the second structure. The method further includes determining that the plurality of stump chains of the first structure includes a faulty latch based on the first result not matching the second result.

The disclosure describes novel methods and apparatuses for controlling a device’s TCA circuit when the device exists in a JTAG daisy-chain arrangement with other devices. The methods and apparatuses allow the TCA test pattern set used during device manufacturing to be reused when the device is placed in a JTAG daisy-chain arrangement with other devices, such as in a customer’s system using the device. Additional embodiments are also provided and described in the disclosure.

A method includes injecting scan patterns into an input of a decompressor that distributes the scan patterns to a plurality of scan chains whose outputs are coupled to inputs of a compressor, which provides a compressed scan test result representing the plurality of scan chains. The method also includes, in response to the compressed scan test result being indicative of failure, identifying a particular scan chain of the plurality of scan chains that is responsible for the failure by a debug circuit that is coupled to the input of the decompressor and to a compressor output. The debug circuit enables an output of any single scan chain of the plurality of scan chains to be available at the compressor output while suppressing outputs of all other scan chains of the plurality of scan chains.

One embodiment of the present disclosure describes a memory system that may include one or more memory devices that may store data. The memory devices may receive command signals to access the stored data as a loopback signal. The memory devices may operate in a normal operational mode, a loopback operational mode, a retrieval operational mode, a non-inverting pass-through operational sub-mode, and an inverting pass-through operational sub-mode. The operational modes facilitate the transmission of the loopback signal for the purpose of monitoring of memory device operations. A selective inversion technique, which uses the operational modes, may protect the loopback signal integrity during transmission.

This application provides decompression circuits. An example decompression circuit includes a plurality of sub-circuits. The sub-circuit includes a plurality of cellular automaton (CA) circuits and a phase shifter. Each of the plurality of CA circuits includes a first XOR circuit and a register. The first XOR circuit includes a first input end, a second input end, and an output end. A data input end of the register is coupled to the output end of the first XOR circuit. A data output end of the register is coupled to the first input end of the first XOR circuit and an input end of the phase shifter. The data output end of the register is further coupled to the second input end of the first XOR circuit in a different CA circuit. The phase shifter is configured to output a test signal.