A test control port (TCP) includes a state machine SM, an instruction register IR, data registers DRs, a gating circuit and a TDO MX. The SM inputs TCI signals and outputs control signals to the IR and to the DR. During instruction or data scans, the IR or DRs are enabled to input data from TDI and output data to the TDO MX and the top surface TDO signal. The bottom surface TCI inputs may be coupled to the top surface TCO signals via the gating circuit. The top surface TDI signal may be coupled to the bottom surface TDO signal via TDO MX. This allows concatenating or daisy-chaining the IR and DR of a TCP of a lower die with an IR and DR of a TCP of a die stacked on top of the lower die.

An integrated circuit includes a data propagation path including a flip-flop. The flip-flop includes a first latch and a second latch. The integrated circuit includes a third latch that acts as a dummy latch. The input of the third latch is coupled to the output of the first latch. The integrated circuit includes a fault detector coupled to the output of the flip-flop and the output of the third latch. The third latch includes a signal propagation delay selected so that the third latch will fail to capture data in a given clock cycle before the second latch of the flip-flop fails to capture the data in the given clock cycle. The fault detector that detects when the third latch is failed to capture the data.

An integrated circuit (IC) includes a clocking system that generates first and second clock signals and a clock enable signal, and a testing system that tests the clocking system. During a capture phase of an at-speed testing mode of the IC, the second clock signal is a gated version of the first clock signal and includes two clock pulses. The testing system determines a first count of clock pulses of the first clock signal between an activation of the capture phase and an assertion of the clock enable signal. Similarly, the testing system determines a second count of clock pulses of the first clock signal between the two clock pulses of the second clock signal. The testing system then compares the first count with a first reference value and the second count with a second reference value to detect a fault in the clocking system.

An integrated circuit for transition fault testing comprises a synchronizing circuit including a first set of shift registers coupled to receive a scan enable signal and to provide a synchronizing signal based on the scan enable signal; a clock leaker circuit coupled to the synchronizing circuit and including a second set of shift registers coupled to receive a first clock signal based on the synchronizing signal and to provide a second clock signal that includes a set of pulses; and a multiplexer (MUX) that includes a first input coupled to receive a shift clock, a second input coupled to the clock leaker circuit to receive the second clock signal, and an output configured to provide an output clock signal that includes a second set of pulses.

Systems, methods, and computer program products directed to testing a System-in-a-Package (SIP) using an Automatic Test Equipment (ATE) machine. A functional representation of one or more tests to be performed in the SIP is loaded in a memory located on a load board, the load board located on the ATE machine. A test controller located on at least one of the SIP and the load board is caused to retrieve and store the one or more tests to be performed in the SIP. The test controller is instructed to conduct the one or more tests in the SIP.

A method of testing an integrated circuit device, that operates at a clock frequency and that has at least one scan chain that includes a plurality of registers separated by combinatorial logic, includes establishing a respective scan chain test pattern for testing the scan chain where the scan chain test pattern includes a respective bit for each register in the plurality of registers of the scan chain, determining in advance a respective timing delay for each pair of adjacent registers in the scan chain, and, within a single clock period of the clock frequency, applying, in parallel, each bit of the respective scan chain pattern to a respective register in the plurality of registers in the scan chain, each bit of the respective scan chain pattern being applied to its respective register at a respective temporal offset, within the single clock period, based on the respective timing delay.

This disclosure describes die test architectures that can be implemented in a first, middle and last die of a die stack. The die test architectures are mainly the same, but for the exceptions mentioned in this disclosure.

This disclosure describes die test architectures that can be implemented in a first, middle and last die of a die stack. The die test architectures are mainly the same, but for the exceptions mentioned in this disclosure.

A circuit comprises a plurality of clock control devices. Each of the clock control devices is configured to generate a scan test clock signal for a particular clock domain in the circuit and comprises circuitry configured to select clock pulses of a fast clock signal as scan capture clock pulses for the particular clock domain based on a particular clock pulse of a slow clock signal and a scan enable signal. The order and spacing between the groups of the scan capture clock pulses for different clock domains correspond to the order and spacing of the clock pulses of the slow clock signal.

A method includes generating a functional clock signal, a scan clock signal, and a delayed clock signal based on a control clock signal and a scan enable signal. The method includes precharging or predischarging a differential pair of nodes in a first latch using the delayed clock signal and a voltage on a first power supply node and controlling a second latch using the delayed clock signal. The method includes latching data input by the first latch using the functional clock signal in a functional mode of operation and latching scan data by the first latch using the scan clock signal in a scan mode of operation.