Stmicroelectronics International N.v.

Umesh Chandra Srivastava

Venkata Narayanan Srinivasan

Manish Sharma

Shiv Kumar Vats

Jeena Mary George

V Narayanan Srinivasan

According to an embodiment, a digital circuit includes an OR gate and a flip-flop. The OR gate includes a first input and a second input. The first input of the OR gate is coupled to a control signal, and the second input of the OR gate is coupled to an uncovered functional combination logic of the digital circuit. The first input of the OR gate is configured to be pulled low by the control signal in response to setting the digital circuit in a configuration to test the uncovered functional combination logic. The flip-flop includes a reset pin or a set pin coupled to the output of the OR gate. The output of the flip-flop is configured to be observed during a testing of the uncovered functional combination logic to detect defects in the digital circuit.

Area, cost, and time-effective scan coverage improvement

An integrated circuit includes a first set and a second set of scan flip flops, a circuit under test, and a controller. Each scan flip flop of the first set includes a scan enable input coupled to a first scan enable signal. The circuit under test includes logic elements downstream of the first set. The second set includes at least one scan flip flop downstream of the logic elements. Each scan flip flop of the second set includes a scan enable input coupled to a second scan enable signal. The controller is configured to test the logic elements by shifting test patterns into the first set while asserting both the first and second scan enable signal, launching the test patterns, and capturing results from the second set while continuing to assert the first scan enable signal and deasserting the second scan enable signal.

Test pattern generation using multiple scan enables

According to an embodiment, a method for testing a triple-voting flop (TVF) is provided. The method includes providing a first and a second scan enable signal by a control circuit to, respectively, a first scan flip-flop and a third scan flip-flop of the TVF; receiving a third scan enable signal at the second scan flip-flop of the TVF; providing a scan input signal to the first scan flip-flop, the second scan flip-flop, and the third scan flip-flop; controlling the first scan enable signal, the second scan enable signal, and the third scan enable signal; receiving, at an output of the TVF, a scan output signal; and determining whether the TVF suffers from a fault based on the scan output signal and the controlling of the first scan enable signal, the second scan enable signal, and the third scan enable signal.

TVF transition coverage with self-test and production-test time reduction

In an embodiment, a method for performing scan testing includes: generating first and second scan clock signals; providing the first and second scan clock signals to first and second scan chains, respectively, where the first and second scan clock signals includes respective first shift pulses when a scan enable signal is asserted, and respective first capture pulses when the scan enable signal is deasserted, where the first shift pulse of the first and second scan clock signals correspond to a first clock pulse of a first clock signal, where the first capture pulse of the first scan clock signal corresponds to a second clock pulse of the first clock signal, and where the first capture pulse of the second scan clock signal corresponds to a first clock pulse of a second clock signal different from the first clock signal.

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Greater Noida, India

Umesh Chandra Srivastava