A method for optimizing a source synchronous clock reference signal timing to capture data from a memory device (e.g., DDR SDRAM) includes conducting an iterative two-dimensional data eye search for optimizing the delay of the source synchronous clock reference signal (e.g., DQS). Embodiments of the present invention are directed to tuning the delay for each device for the optimal margin in two dimensions: maximize the distance from the data eye walls and maximize the noise margin on the interfa...

A method is provided for generating electrical test patterns for testing functional AC parameters of integrated semiconductor circuits from the test patterns used for the more conventional testing of the DC parameters of such circuits. The AC parameters include such factors as rise time, fall time and circuit delays. Starting with a DC pattern known to be sufficient for the DC testing of the circuit to be tested, each increment of the DC pattern which comprises a plurality of parallel bilevel si...

In a system for generating tests for digital circuits, a fault simulator (16) simulates a fault-free version of the circuit and all expected faulty versions of it concurrently, basing its operation on information contained in a data base (12) that contains information about the structure and possible defects of the circuits to be tested. A waveform system (14) carries high-level information regarding the general structure of the test waveform that ultimately is to be derived, such as clock signa...

A path oriented decision making test pattern generator is embodied in a logic chip test system for testing large-scale integrated circuits having many internal nodes inaccessible to the test probes of chip testing machines. For each designated possible chip fault, consisting of a stuck-high or stuck-low voltage at a node of the chip logic network, the generator provides a test pattern of signals to be applied to the input pins of each chip, so that the resulting signal at an output pin indicates...

Disclosed is a technique for testing highly complex, functional logic where long sequences of test patterns are needed. A logic network to be tested comprises a large number of logic blocks. The inputs to several of these logic blocks are also the primary inputs (PI) to the logic network to be tested while the output of several of the logic blocks are also outputs (PO) of the logic network to be tested. However, the inputs and outputs of many logic blocks of the network to be tested are inaccess...

An efficient method and apparatus for characterizing circuit devices is disclosed. In one embodiment, multiple test patterns for testing a circuit device are stored in a tester. Each test pattern includes both test data and control data that defines at least in part a sweep point at which the circuit device is tested. Thus, the tester can generate stimulus vectors for multiple sweep points without requiring control system intervention. Pass/fail indicators, each of which represents pass/fail res...

An apparatus being able to not only detect a manufacturing defect of an integrated circuit but also specify a position at which the defect occurs even when outputs from scan paths are compressed and stored, or when the number of the scan paths is large. The apparatus has a pattern generator built in an integrated circuit to generate test patterns, a plurality of shift registers formed in parallel, into which the test patterns are shifted, and an output compressor for compressing a plurality of o...

Disclosed is a system and method for testing electronic devices which uses a random pattern for testing electronic devices. In one embodiment there is communicated to a device under test (DUT) a test sequence causing the DUT to exercise certain parameters in a controlled pattern of operation. The test sequence is randomly created. In one embodiment this random creation is controlled by a random looping algorithm which controls both the order of and the magnitude of each parameter. Included, if d...

In the present invention a method for generating tests for a combinational logic circuit of the PLA type is disclosed. The method is suited to generate tests to determine the input signals, the mid-term output signals of the AND gates, and the output signals, for stuck-at-0 and stuck-at-1 conditions.

An electronic device under test (DUT) responds to a digital input signal by generating a digital DUT output signal conveying a repetitive digital signal pattern. An apparatus for measuring various characteristics of the DUT output signal includes a trigger generator for generating a series of trigger signal edges in response to selected DUT output signal edges occurring during separate repetitions of the digital signal pattern. The trigger generator can be configured to generate each trigger sig...