A semiconductor device addresses to a problem in which a current consumption variation rate increases during BIST execution causing resonance noise generation in a power supply line. The semiconductor device includes a self-diagnosis control circuit, a scan target circuit including a combinational circuit and a scan flip-flop, and an electrically rewritable non-volatile memory. A scan chain is configured by coupling a plurality of the scan flip-flops. In accordance with parameters stored in the non-volatile memory, the self-diagnosis control circuit can change a length of at least one of a scan-in period, a scan-out period and a capture period, and can also change a scan start timing.

A circuit device is provided with a first codec including a first portion of a logic circuit and a second codec including a second portion of the logic circuit. The circuit device can also include a plurality of first scan chains coupled to the first codec and configured to shift a delayed test vector onto the first codec, wherein the delayed test vector is a test vector with a phase delay. A plurality of second scan chains can be coupled to the second codec and configured to shift the test vector onto the second codec.

A semiconductor integrated circuit includes scan chains, each of which includes a serial connection of sequential circuits and performs a shift register operation in a scan test; and an integrated clock gating (ICG) chain composed by coupling, to one another, ICG circuits, each of which individually supplies a corresponding one of the scan chains with a circuit clock signal to operate the sequential circuits. In the ICG chain, an ICG enable propagation signal for controlling timing when the ICG circuits output the circuit clock signals propagates through a signal line and is input sequentially to the ICG circuits. The ICG circuits output the circuit clock signals at respective timings that are different among the scan chains.

An extended joint test action group based controller and a method of use allows easier testing of integrated circuits by reducing the power dissipation of an IC. The extended joint test action group (JTAG) controller tests internal storage elements that form digital units in an integrated circuit (IC) use a design for testing scan infrastructure on the IC, wherein the JTAG controller is extended by an overall reset generator for all digital units of the IC, and a finite state machine controls the overall reset generator. In reset mode the JTAG controller stops the at least one clock module in supplying the digital units that should be reset. It then sets all scan chains in test mode and switches the input multiplexers into reset mode; and then controls the number of shift clock cycles for shifting in the reset value to the flip-flops in the scan chain, respectively.

A method of power test analysis for an integrated circuit design including loading test vectors into a first sequence of flip-flops in scan mode, evaluating the test vectors and saving results of the evaluating in a second sequence of flip-flops in scan mode, reading results out of the second sequence of flip-flops to a scan chain, and calculating power generation based on the results. In one embodiment, the test vectors are received from an automatic test pattern generator.

Described herein are integrated circuit chips having test circuitry designed such that independently selectable testing of different power domains using a same scan chain compressor-decompressor circuit may be performed. Also disclosed herein are integrated circuit chips having test circuitry designed such that independently selectable testing of different power domains using multiple different scan chain compressor-decompressor circuits may be performed.

Testing of die on wafer is achieved by; (1) providing a tester with the capability of externally communicating JTAG test signals using simultaneously bidirectional transceiver circuitry, (2) providing die on wafer with the capability of externally communicating JTAG test signals using simultaneously bidirectional transceiver circuity, and (3) providing a connectivity mechanism between the bidirectional transceiver circuitry's of the tester and a selected group or all of the die on wafer for communication of the JTAG signals.

A clock control system for a scan chain generates two clock signals. During a shift phase of a testing mode of the scan chain, one clock signal is an inverted version of the other clock signal. The clock control system provides the clock signal and the inverted clock signal to two different scan flip-flops of the scan chain, respectively. Each of the two scan flip-flops performs a flip-flop operation when the received clock signal transitions from a de-asserted state to an asserted state. Thus, the two flip-flop operations are mutually exclusive during the shift phase. As a result, a dynamic voltage drop across the scan chain during the shift phase is reduced.

An integrated circuit device includes a plurality of cells or modules. Each respective one of the cells or modules consumes leakage power, and the amount of leakage power consumed by a respective one of the cells or modules varies depending on states of its inputs. Scan-chain circuitry is configured to propagate through the integrated circuit device, on entry of the integrated circuit device to a low-power mode, a scan-chain pattern created in advance, to apply, to each respective cell or module in the low-power mode, a set of inputs that results in a respective low-power state with reduced leakage power. Creating the scan chain pattern includes identifying respective ones of the cells or modules as having the highest leakage power consumption, and a respective combination of inputs to place each of those the cells or modules in a respective low-power state.

Described herein are integrated circuit chips having test circuitry designed such that independently selectable testing of different power domains using a same scan chain compressor-decompressor circuit may be performed. Also disclosed herein are integrated circuit chips having test circuitry designed such that independently selectable testing of different power domains using multiple different scan chain compressor-decompressor circuits may be performed.