Lsi Corporation

Lsi Logic Corporation

Arun K Gunda

Narendra Devta-Prasanna

Kaushik De

Sreejit Chakravarty

Thai Minh Nguyen

Grant A Lindberg

Fan Yang

Saket K Goyal

Sandeep Kumar Goel

Hunaid Hussain

Pradipta Ghosh

Ahmad A Alvamani

Venkat C Ghanta

Sharad Prasad

Narendra B Devta-Prasa

Siva Venkatraman

A system and device for reducing instantaneous voltage droop (IVD) during a scan shift operation. In one embodiment, a system includes a first group of clock gating cells configured to receive an input clock signal and a first group of flip-flops coupled to the first group of clock gating cells. Each clock gating cell of the first group of clock gating cells includes a first delay element to delay the input clock signal by a first duration during a scan shift operation. The system also includes a second group of clock gating cells configured to receive the input clock signal, and a second group of flip-flops coupled to the second group of clock gating cells. Each clock gating cell of the second group of clock gating cells includes a second delay element to delay the input clock signal by a second duration during the scan shift operation.

System and device for reducing instantaneous voltage droop during a scan shift operation

A scan clock modifier, a method of providing a variable scan clock, an IC including a scan clock modifier and a library including a cell of a scan clock modifier. In one embodiment, the scan clock modifier includes: (1) logic circuitry configured to provide at least one selected clock signal based on a test scan clock signal and a first clock control signal, both of the test scan clock signal and the first clock control signal received from test equipment and (2) comparison logic configured to provide a scan clock signal based on the at least one selected clock signal and at least one other clock control signal received from the test equipment, wherein the first and the at least one other clock control signals are different clock control signals.

Test technique to apply a variable scan clock including a scan clock modifier on an integrated circuit

A test system tests a circuit. Compressed scan data subsets are stored, one at a time, in a memory of the test system. The multiple compressed scan data subsets correspond with multiple scan chains in a function block of the tested circuit. Transmission of the compressed scan data subset from the memory to the tested circuit is controlled by the test system. The test system receives a compacted test output subset from the tested circuit and provides a test system output that indicates a presence of any errors in functioning of the tested circuit.

Testing a circuit with compressed scan chain subsets

A method for implementing test generation for systematic scan reconfiguration in an integrated circuit is presented. The method may comprise: defining at least one set of detectable faults; setting an SAS decoder configuration, the SAS decoder configuration including a don't-care bit; generating an ATPG pattern; and applying the ATPG pattern to one or more scan chain segments having a segment address associated with the SAS decoder configuration.

Method for implementing test generation for systematic scan reconfiguration in an integrated circuit

The present invention is directed to a system and method for quality improvement by identifying test patterns for DFT logic faults and functional logic faults. The identified test patterns may be selectively utilized for pruning of patterns or DPM estimation. Functional faults and DFT faults may be identified from detected TDF faults. The functional faults are faults on a logic which was present in a pre-test insertion net list. Remaining faults are the DFT faults. A set of test patterns for DFT faults may be utilized as the first target for the pattern truncation which will reduce the amount of test patterns to be tested. A set of test patterns for functional may be utilized for improving the TDF coverage.

Method and system for improving quality of a circuit through non-functional test pattern identification

The present invention is directed to a system and method for improving transition delay test coverage through use of enhanced flip flops (ES flip-flops) for a broadside test approach. Each ES flip-flop includes a two port flip-flop including a first flip-flop and a second flip-flop. A separate control input (ESM) which is not time critical is used to select a multiplexer of the second flip-flop. Thus, the ES flip-flops do not require a fast signal switching between launch and test response capture or an extra clock signal. Various enhanced scan modes may be selected via a combination of SEN and ESM. Moreover, only a heuristically selected subset of scan flip-flops may be replaced with the ES flip-flops so as to minimize the length of a scan chain as well as the logic area overhead. The present invention provides high TDF coverage under the broadside testing.

System and method for improving transition delay fault coverage in delay fault tests through use of an enhanced scan flip-flop

The present invention is directed to a system and method for improving transition delay fault coverage through use of augmented flip-flops (TL flops) for a broadside test approach. The TL flops use the same clock for scan and functional operation. Thus, the TL flops do not require a fast signal switching between launch and test response capture. Each of the TL flops includes additional multiplexer in front of a standard scan flop and a transition enable (TEN) signal. Moreover, only a heuristically selected subset of scan flip-flops is replaced with the TL flops and only one additional MUX per selected scan flip-flop may contribute an area overhead. Consequently, the overall chip area overhead may be minimal. The present invention may be suitable for being implemented with currently available third party ATPG.

System and method for improving transition delay fault coverage in delay fault tests through use of transition launch flip-flop

A method and apparatus are provided for analyzing test vectors for use in measuring static current consumed by an integrated circuit. A netlist of interconnected cells is read to identify cell types used within the netlist, wherein the netlist includes a plurality of nodes. Once the netlist has been read, cell characteristics for selected ones of the cell types are read from a technology library to identify pins of the selected cell types to be monitored. The nodes in the netlist that correspond to these pins are identified and are added to an list file. Once the list file has been generated, a computer simulation program is used to simulate a steady-state response of a functional model of the integrated circuit to a potential test vector and to output the resulting logic states on the nodes provided in the list file.

Method of analyzing static current test vectors with reduced file sizes for semiconductor integrated circuits

A system and method identifies Iddq test vectors to be used in IDDQ testing of large CMOS circuits. This is achieved through intelligent preprocessing techniques. By monitoring only those nodes in the circuit that may be responsible for leakage current in the steady state, the size of the simulation results file is drastically reduced. The reduced simulation results file makes simulation a viable solution for IDDQ vector identification.

IDDQ test solution for large asics

A reduced netlist representing only partial netlist information for a logic block such as an ASIC embedded core is generated, such that proprietary information contained within the netlist can be kept confidential. The core is conceptually divided into a first section that can be completely tested using only a serial scan port, and a second section that can be tested in isolation from the first section using both primary inputs to the core as well as scan inputs. Netlist information for the first section is removed from the netlist, and the customer is supplied with serial scan test vectors that test the first section. Additionally, a multiplexing circuit selects either a serial scan chain for the entire logic block, or a scan chain that does not include scan cells within the first section of the logic bloc.

Test shells for protecting proprietary information in asic cores

A method and apparatus for isolating faults in an integrated circuit reduces time and effort to precisely locate such faults. A fault dictionary is developed, which is a record of the errors a circuit's modeled faults are expected to cause. The fault dictionary need only be generated once, and can be recalled for later testing of the same design. A failing circuit is subjected to test vectors and the erroneous outputs are logged, and then all failing scan test vectors are mapped into simulation scan patterns. Faults in the circuit are localized to a more narrowly defined area in which faults in the circuit may occur. If the area, even after localization, is too large, additional test patterns are developed and the device is subjected to another round of tests. The redefinition of test patterns is repeated until possible fault locations are sufficiently localized. The device is then probed to precisely locate the fault(s).

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San Jose, CA, United States of America

Arun K Gunda