A critical data path of an integrated circuit includes a flip flop configured to receive a data input and provide a latched data output. A monitoring circuit includes a delay generator configured to receive the data input and provide a plurality of delayed data outputs corresponding to delayed versions of the data input with increasing amounts of delay, a selector circuit configured to select one of the plurality of delayed outputs based on a programmable control value, and a shadow latch coupled to an output of the selector circuit and configured to latch a value at its input to provide as a latched shadow output. A comparator circuit provides a match error indicator based on a comparison between the first latched data output and the latched shadow output, and an error indicator is provided which indicates whether or not an impending failure of the critical data path is detected.

A method of testing a data transmission and reception system comprises sending a test signal from a transmitter (14) of the system to a receiver (12) of the system, and analyzing the received signal. A duty cycle relationship is varied between the test signal and the timing signal used by the receiver of the system, and the effect of the duty cycle variation is analyzed. Varying the duty cycle relationship provides duty cycle distortion (DCD), and this can be considered as a form of embedded jitter insertion. This type of jitter can be measured relatively easily.

Embodiments of the present invention provide an automated test equipment (a “tester”) for testing a device under test, including a bidirectional dedicated real-time handler interface. Some embodiments include an interface having a trigger function, a fixed endpoint interface, an interface arranged on a test head, and/or a number of lines/communication channels adapted to a specific communication task, without separate signal lines, for example. The bidirectional dedicated real-time handler interface can be used to transmit a synchronization signal or other information to the handler in real-time, and the transmitted signal can be test site specific. The real-time signaling advantageously improves testing accuracy and efficiency.

This disclosure describes a test architecture that supports a common approach to testing individual die and dies in a 3D stack arrangement. The test architecture uses an improved TAP design to facilitate the testing of parallel test circuits within the die.

A test mode signal is generated to include a test pattern and an error reporting sequence. The test mode signal is sent on link that includes one or more extension devices and two or more sublinks. The test mode signal is to be sent on a particular one of the sublinks and is to be used by a receiving device to identify errors on the particular sublink. The error reporting sequence is to be encoded with error information to describe error status of sublinks in the plurality of sublinks.

A delay measurement circuit includes a transporting path selector, first and second delay measurement devices, and a controller. The delay measurement circuit forms a plurality of transporting loops through two of a first reference transporting conductive wire, a second reference transporting conductive wire, and a tested transporting conductive wire according to a control signal. The first delay measurement device respectively measures part of the transporting loops to obtain a plurality first transporting delays. The second delay measurement device respectively measures part of the transporting loops to obtain a plurality second transporting delays. The controller generates the control signal, and obtains a transporting delay of the tested transporting conductive wire according to the first transporting delays and the second transporting delays.

Embodiments are directed to a computer implemented method and system for the testing, characterization and diagnostics of integrated circuits. A system might include a device under test, such as an integrated circuit, that includes an adaptive microcontroller. The method includes loading a testing program for execution by the adaptive microcontroller, causing the microcontroller to execute the testing program. Once results from the testing program are received, the testing program can be adaptively modified based on the results. The modified testing program can be run again. The testing program can modify parameters of the integrated circuit that are not externally accessible. Other embodiments are also disclosed.

An apparatus for testing a device under test (DUT) is provided. The apparatus includes a power supply device and a data generating device. The power supply device is configured to provide a first voltage and a second voltage to the DUT. The data generating device is configured to provide first data to the DUT. The power supply device is configured to provide the first voltage to the DUT in a first time duration. The data generating device is configured to provide the first data to the DUT in the first time duration. The power supply device is configured to provide the second voltage to the DUT in a second time duration after the first time duration. The second voltage is different from the first voltage.

A method is presented for characterizing a digital circuit for determining an optimum operating point of the digital circuit. The digital circuit includes sequential elements; conducting data paths; a clock tree; a time fault sensor receiving as input a data signal and configured to detect during a detection window a transition of the data signal; and a system for setting first and second operating parameters of the circuit. The method includes a) activating a conducting data path leading to the sequential element coupled to the sensor; b) determining, for a given value of the first parameter, a first value of the second parameter from which the sensor detects a transition of the data signal during the detection window, the values of the first and second parameters defining an operating point of the circuit; and c) correcting the operating point.

A virtual critical path (VCP) circuit is defined separate from an actual critical path circuit. The VCP operates in accordance with a special clock signal. The actual critical path circuit operates in accordance with a system clock signal. The VCP circuit has a signal timing characteristic substantially equal to that of the actual critical path circuit. The VCP circuit includes computational circuitry defined to compute an output value based on an input value, and comparison circuitry defined to compare the output value with an expected result value. A match between the output value computed by the VCP circuit and the expected result value indicates that a frequency of the special clock signal is acceptable. The VCP circuit is used to determine a maximum acceptable frequency of the special clock signal. A frequency of the system clock signal is then set to the maximum acceptable frequency of the special clock signal.