Abstract: In an embodiment, the amount of supply voltage guardband to prevent incorrect operation due to aging effects may be modeled using an IC-specific age model generated early in the product life cycle of the IC. For example, high temperature operating life (HTOL) testing may be performed at multiple temperatures and/or voltages to develop the IC-specific age model. The IC-specific age model may be more accurate then the calculations used to develop guardband voltage as discussed previously, which rely on the aging of a single transistor. The IC-specific age model may be used along with monitoring of the aging effects during operation of the IC to predict an amount of increased guardband voltage that is currently desirable to apply to the IC. The predicted amount may vary from about zero when the IC is new to the full amount of guardband voltage when the IC is nearing end of life.

Abstract: An apparatus and method for testing driver write-ability strength on an integrated circuit includes one or more drive detection units each including a number of drivers. At least some of the drivers may have a different drive strength and each may drive a voltage onto a respective driver output line. Each drive detection unit may include a number of keeper circuits, each coupled to a separate output line and configured to retain a given voltage on the output line to which it is coupled. Each detection unit may also include a number of detection circuits coupled to detect the drive voltage on each of the output lines. In one implementation, the drive voltage appearing at the output line of each driver may be indicative of that the driver was able to overdrive the voltage being retained on the output line to which it is coupled by the respective keeper circuits.

Abstract: In an embodiment, a clocked storage device such as a pulse flop is provided. The pulse flop includes a latch coupled to receive a scan data input to the pulse flop. The latch receives the scan data input during one of the phases of the clock, and retains the received input during the other phase. The other phase is the phase in which the pulse to the pulse flop occurs. Thus, when scan data is captured in the pulse flop, the latch at the next pulse flop in the chain may be closed and may prevent a race condition in propagating the scan data.

Abstract: An apparatus and method for testing driver write-ability strength on an integrated circuit includes one or more drive detection units each including a number of drivers. At least some of the drivers may have a different drive strength and each may drive a voltage onto a respective driver output line. Each drive detection unit may include a number of keeper circuits, each coupled to a separate output line and configured to retain a given voltage on the output line to which it is coupled. Each detection unit may also include a number of detection circuits coupled to detect the drive voltage on each of the output lines. In one implementation, the drive voltage appearing at the output line of each driver may be indicative of that the driver was able to overdrive the voltage being retained on the output line to which it is coupled by the respective keeper circuits.

Abstract: An apparatus and method for testing sense amplifier threshold voltages on an integrated circuit includes one or more sense amplifier modules each including a number of sense amplifier circuits, a voltage generator unit, and detection logic. The voltage generator unit may select a differential voltage to supply to at least some of the sense amplifier circuits, and each sense amplifier circuit may be configured to generate an output value that is dependent upon the applied differential voltage in response to receiving an enable signal. The detection logic may detect and capture an output value of each of the sense amplifier circuits. In one implementation, the voltage generator unit may iteratively select a different differential voltage in response to a control input. Accordingly, the detection logic may capture the output value of the sense amplifiers after each change in differential voltage.

Abstract: An apparatus and method for testing driver write-ability strength on an integrated circuit includes one or more drive detection units each including a number of drivers. At least some of the drivers may have a different drive strength and each may drive a voltage onto a respective driver output line. Each drive detection unit may include a number of keeper circuits, each coupled to a separate output line and configured to retain a given voltage on the output line to which it is coupled. Each detection unit may also include a number of detection circuits coupled to detect the drive voltage on each of the output lines. In one implementation, the drive voltage appearing at the output line of each driver may be indicative of that the driver was able to overdrive the voltage being retained on the output line to which it is coupled by the respective keeper circuits.

Abstract: A mechanism for measuring the variability of the read current of SRAM cells on an integrated circuit includes the integrated circuit having an SRAM array including a plurality of SRAM cells. The integrated circuit may also include a selection circuit configured to select a particular SRAM cell in response to a selection input. An oscillator circuit such as a ring oscillator, for example, on the integrated circuit may be configured to oscillate at a frequency that is dependent upon a read current of a selected SRAM cell during operation in a first mode. A frequency determining circuit that is coupled to the oscillator circuit may be configured to output a value corresponding to the frequency of oscillation of the oscillator circuit.

Abstract: In an embodiment, a clocked storage device such as a pulse flop is provided. The pulse flop includes a latch coupled to receive a scan data input to the pulse flop. The latch receives the scan data input during one of the phases of the clock, and retains the received input during the other phase. The other phase is the phase in which the pulse to the pulse flop occurs. Thus, when scan data is captured in the pulse flop, the latch at the next pulse flop in the chain may be closed and may prevent a race condition in propagating the scan data.

Abstract: An apparatus and method for testing level shifter threshold voltages on an integrated circuit includes one or more level shifter modules each including a number of level shifter circuits. Each level shifter circuit may be coupled to a first and a second voltage supply. Each level shifter circuit may also receive an input signal that is referenced to the first voltage supply, and to generate an output signal that is referenced to the second voltage supply. In addition, each level shifter module may include detection logic that may detect an output value of each of the level shifter circuits. The control circuit may be configured to iteratively change the voltage output from one of the voltage supplies, and maintaining a voltage on the other voltage supply while the input signal is provided to the level shifter circuits. The detection logic may capture the output value upon each change in voltage.

Abstract: An apparatus and method for testing sense amplifier threshold voltages on an integrated circuit includes one or more sense amplifier modules each including a number of sense amplifier circuits, a voltage generator unit, and detection logic. The voltage generator unit may select a differential voltage to supply to at least some of the sense amplifier circuits, and each sense amplifier circuit may be configured to generate an output value that is dependent upon the applied differential voltage in response to receiving an enable signal. The detection logic may detect and capture an output value of each of the sense amplifier circuits. In one implementation, the voltage generator unit may iteratively select a different differential voltage in response to a control input. Accordingly, the detection logic may capture the output value of the sense amplifiers after each change in differential voltage.

Abstract: A mechanism for measuring the variability of the read current of SRAM cells on an integrated circuit includes the integrated circuit having an SRAM array including a plurality of SRAM cells. The integrated circuit may also include a selection circuit configured to select a particular SRAM cell in response to a selection input. An oscillator circuit such as a ring oscillator, for example, on the integrated circuit may be configured to oscillate at a frequency that is dependent upon a read current of a selected SRAM cell during operation in a first mode. A frequency determining circuit that is coupled to the oscillator circuit may be configured to output a value corresponding to the frequency of oscillation of the oscillator circuit.

Abstract: An apparatus and method for testing driver write-ability strength on an integrated circuit includes one or more drive detection units each including a number of drivers. At least some of the drivers may have a different drive strength and each may drive a voltage onto a respective driver output line. Each drive detection unit may include a number of keeper circuits, each coupled to a separate output line and configured to retain a given voltage on the output line to which it is coupled. Each detection unit may also include a number of detection circuits coupled to detect the drive voltage on each of the output lines. In one implementation, the drive voltage appearing at the output line of each driver may be indicative of that the driver was able to overdrive the voltage being retained on the output line to which it is coupled by the respective keeper circuits.

Abstract: An apparatus and method for testing level shifter threshold voltages on an integrated circuit includes one or more level shifter modules each including a number of level shifter circuits. Each level shifter circuit may be coupled to a first and a second voltage supply. Each level shifter circuit may also receive an input signal that is referenced to the first voltage supply, and to generate an output signal that is referenced to the second voltage supply. In addition, each level shifter module may include detection logic that may detect an output value of each of the level shifter circuits. The control circuit may be configured to iteratively change the voltage output from one of the voltage supplies, and maintaining a voltage on the other voltage supply while the input signal is provided to the level shifter circuits. The detection logic may capture the output value upon each change in voltage.

Abstract: In one embodiment, a jitter detector comprises a logic circuit coupled to receive a plurality of inputs indicative of states captured from a plurality of outputs of a delay chain responsive to a first clock input and a plurality of clocked storage devices coupled to the logic circuit. The logic circuit is configured to identify a first input of the plurality of inputs that is: (i) captured in error from a corresponding one of the plurality of outputs of the delay chain, and (ii) the corresponding one of the plurality of outputs of the delay chain is least delayed by the delay chain among the plurality of outputs that are captured in error. The plurality of clocked storage devices are configured to accumulate an indication of which of the plurality of outputs have been captured in error over a plurality of clock cycles of the first clock input.

Abstract: In one embodiment, an integrated circuit includes at least one digital leakage detector that includes digital circuitry configured to detect an approximation of a magnitude of the leakage current in transistors of the integrated circuit and configured to generate a digital output representing the approximated magnitude. In another embodiment, a leak detector includes leak circuits and clocked storage devices. Each leak circuit is configured to generate an output signal indicative of a different magnitude of leakage current in a transistor. The clocked storage devices are configured to capture a state representing the output signals of the leak circuits. In another embodiment, a method includes running a test for leakage current in a digital leakage detector, wherein a digital output of the digital leakage detector represents a magnitude of a leakage current being experienced by the integrated circuit during use; and outputting the digital output from the integrated circuit.