Abstract: A power supply in a test and measurement device includes a stimulus having an output coupled to an amplifier in which an output signal from the stimulus controls an output level of the amplifier. The stimulus may include a Digital to Analog Converter. A measurement circuit detects the output level of the amplifier. The power supply includes an overpulse generator that can be structured to accept a desired amplifier output level, overdrive the stimulus at a first level for a first time period, and drive the stimulus at a second level for a second time period. The measurement circuit determines when the overpulse generator switches from driving the stimulus at the first level to driving the stimulus at the second level. The time period for driving the stimulus at the second level starts as the actual amplifier output level approaches the desired amplifier output level.

Abstract: A feedback ammeter, which may be included in a source measure unit or a digital multi-meter, for example, including an operational amplifier having an input and an output and a feedback path electrically coupled between the output and the input of the operational amplifier. The feedback path includes a first non-linear device to allow the measurement of decades of current. The ammeter also includes an amplifier electrically coupled to the input of the operational amplifier and the output of the operational amplifier, a second non-linear device electrically coupled to an output of the amplifier, and a resistor electrically coupled between the second capacitor and the input of the operational amplifier. A constant resistance input impedance is established using the second non-linear device that can adjust the circuit gain.

Abstract: A test and measurement device including a source configured to output a source signal, a source output configured to output the source signal to a connected cable, a guard drive circuit electrically coupled to the source and configured to receive the source signal and generated a guard drive signal, the guard drive circuit having a gain less than one, and a guard drive circuit output configured to output the guard drive signal to a connected guard.

Abstract: A power supply in a test and measurement device includes a stimulus having an output coupled to an amplifier in which an output signal from the stimulus controls an output level of the amplifier. The stimulus may include a Digital to Analog Converter. A measurement circuit detects the output level of the amplifier. The power supply includes an overpulse generator that can be structured to accept a desired amplifier output level, overdrive the stimulus at a first level for a first time period, and drive the stimulus at a second level for a second time period. The measurement circuit determines when the overpulse generator switches from driving the stimulus at the first level to driving the stimulus at the second level. The time period for driving the stimulus at the second level starts as the actual amplifier output level approaches the desired amplifier output level.

Abstract: A test and measurement device including a source configured to output a source signal, a source output configured to output the source signal to a connected cable, a guard drive circuit electrically coupled to the source and configured to receive the source signal and generated a guard drive signal, the guard drive circuit having a gain less than one, and a guard drive circuit output configured to output the guard drive signal to a connected guard.

Abstract: A mechanism is disclosed for mitigating common mode current in a test and measurement device. A measurement current can be received from a device under test via a measurement lead that couples a transformer in the test and measurement device with the device under test. The test and measurement device can then be calibrated to apply a nulling current to cancel the common mode current from the measurement current. Other embodiments can be described and/or claimed herein.

Abstract: A feedback ammeter, which may be included in a source measure unit or a digital multi-meter, for example, including an operational amplifier having an input and an output and a feedback path electrically coupled between the output and the input of the operational amplifier. The feedback path includes a first non-linear device to allow the measurement of decades of current. The ammeter also includes an amplifier electrically coupled to the input of the operational amplifier and the output of the operational amplifier, a second non-linear device electrically coupled to an output of the amplifier, and a resistor electrically coupled between the second capacitor and the input of the operational amplifier. A constant resistance input impedance is established using the second non-linear device that can adjust the circuit gain.

Abstract: A mechanism is disclosed for mitigating common mode current in a test and measurement device. A measurement current can be received from a device under test via a measurement lead that couples a transformer in the test and measurement device with the device under test. The test and measurement device can then be calibrated to apply a nulling current to cancel the common mode current from the measurement current. Other embodiments can be described and/or claimed herein.

Abstract: An impedance sourcing circuit for a measurement device configured to measure a device under test (DUT) and method are disclosed. The impedance sourcing circuit includes a voltage/current source. An electrically controlled variable resistance having a control input is configured to adjust the variable resistance is coupled to the DUT. A loop gain controller is coupled to the control input of the electrically controlled variable resistance. The loop gain controller is configured to drive the control input of the electrically controlled variable resistance to adjust the variable resistance to generally match the impedance of the DUT. The impedance sourcing circuit may also include a voltage detector configured to detect a voltage across the DUT and a voltage reference. The loop gain controller may be configured to drive the control input of the electrically controlled variable resistance based on the voltage detected across the DUT and the voltage reference.

Abstract: An RF testing method and system by which a DC measurement pathway can also act like a properly terminated RF pathway. Achieving this requires that the output HI, LO, and Sense HI conductors are terminated in a frequency selective manner such that the terminations do not affect the SMU DC measurements. Once all SMU input/output impedances are controlled, as well as properly terminated to eliminate reflections, the high-speed devices will no longer oscillate during device testing, so long as the instruments maintain a high isolation from instrument-to-instrument (separate instruments are used on the gate and drain, or on the input and output of the device). The output of HI, LO and Sense HI conductors are coupled to various nodes of the DUT via three triaxial cables, the outer shieldings of which are coupled to each other and to an SMU ground.

Abstract: A device with low dielectric absorption includes a printed circuit board (PCB), a component connection area including a first conductor layered on a top surface of the component connection area and a second conductor layered on a bottom surface of the component connection area, an aperture surrounding the component connection area, a low-leakage component connecting the component connection area to the PCB across the aperture, and a guard composed of a third conductor at least substantially surrounding the aperture on a top surface of the PCB and a fourth conductor at least substantially surrounding the aperture on a bottom surface of the PCB.

Abstract: A device with low dielectric absorption includes a printed circuit board (PCB), a component connection area including a first conductor layered on a top surface of the component connection area and a second conductor layered on a bottom surface of the component connection area, an aperture surrounding the component connection area, a low-leakage component connecting the component connection area to the PCB across the aperture, and a guard composed of a third conductor at least substantially surrounding the aperture on a top surface of the PCB and a fourth conductor at least substantially surrounding the aperture on a bottom surface of the PCB.

Abstract: A measurement instrument for measuring the impedance of a device under test (DUT) includes a first source of either a voltage or a current and a second source of either a voltage or a current, wherein the first source is connectable in a first feedback relationship with the DUT and the second source is connectable in a second feedback relationship with both the DUT and the first source. The first and second sources are operated respectively as a current source responsive to the current through the DUT and a voltage source responsive to the voltage across the DUT or operated respectively as a voltage source responsive to the voltage across the DUT and a current source responsive to the current through the DUT. The second feedback relationship has a narrower bandwidth than the first feedback relationship. The resulting voltage across the DUT and the current through the DUT establish the measured impedance of the DUT.

Abstract: An RF testing method and system by which a DC measurement pathway can also act like a properly terminated RF pathway. Achieving this requires that the output HI, LO, and Sense HI conductors are terminated in a frequency selective manner such that the terminations do not affect the SMU DC measurements. Once all SMU input/output impedances are controlled, as well as properly terminated to eliminate reflections, the high-speed devices will no longer oscillate during device testing, so long as the instruments maintain a high isolation from instrument-to-instrument (separate instruments are used on the gate and drain, or on the input and output of the device). The output of HI, LO and Sense HI conductors are coupled to various nodes of the DUT via three triaxial cables, the outer shieldings of which are coupled to each other and to an SMU ground.

Abstract: An impedance sourcing circuit for a measurement device configured to measure a device under test (DUT) and method are disclosed. The impedance sourcing circuit includes a voltage/current source. An electrically controlled variable resistance having a control input is configured to adjust the variable resistance is coupled to the DUT. A loop gain controller is coupled to the control input of the electrically controlled variable resistance. The loop gain controller is configured to drive the control input of the electrically controlled variable resistance to adjust the variable resistance to generally match the impedance of the DUT. The impedance sourcing circuit may also include a voltage detector configured to detect a voltage across the DUT and a voltage reference. The loop gain controller may be configured to drive the control input of the electrically controlled variable resistance based on the voltage detected across the DUT and the voltage reference.

Abstract: A power supply includes: a switching amplifier including an input and an output, the amplifier input being adapted to be powered by an electrical power source; a transformer including a primary and a secondary winding on a magnetic core, the number of winding turns being chosen to limit magnetization levels to avoid magnetic saturation while maximizing winding spacing, the transformer primary winding being in communication with the amplifier output; a rectification system in communication with the transformer secondary winding, the rectification system providing a DC power output; and a controller. The controller monitors the DC power output and adjusts the switching amplifier in response to the monitoring to provide a desired power output characteristic.

Abstract: A test head for testing a DUT includes a probe card having a plurality of DUT probes, the probes being in contact with the DUT during the testing; an instrument carrier, the instrument carrier being located above the DUT during the testing; and a SMU mounted on the carrier for each of the probes, each SMU being operably connectable to a respective probe, wherein the carrier is moved with respect to the probe card to permit replacement of the probe card.

Abstract: A measurement instrument for measuring the impedance of a device under test (DUT) includes a first source of either a voltage or a current and a second source of either a voltage or a current, wherein the first source is connectable in a first feedback relationship with the DUT and the second source is connectable in a second feedback relationship with both the DUT and the first source. The first and second sources are operated respectively as a current source responsive to the current through the DUT and a voltage source responsive to the voltage across the DUT or operated respectively as a voltage source responsive to the voltage across the DUT and a current source responsive to the current through the DUT. The second feedback relationship has a narrower bandwidth than the first feedback relationship. The resulting voltage across the DUT and the current through the DUT establish the measured impedance of the DUT.

Abstract: A solid state switch includes a solid state device having an input terminal, an output terminal and a gate terminal; a quick response circuit selectively operable to initially place the solid state device in a conducting state; and a sustained response circuit selectively operable to maintain the solid state device in the conductive state after the quick response circuit. The input terminal and the output terminal are connected when the solid state device is in the conducting state and the input and the output terminal are disconnected when the solid state device is not in the conducting state.

Abstract: A guarded sense impedance for use in a measurement instrument includes a sense impedance adapted to have a spatially distributed electrical potential and at least one guard structure adapted to have the spatially distributed electrical potential. The guard structure is arranged to provide a spatially distributed guard potential for the sense impedance.