Abstract: Circuitry and methods of operating the same to strobe a DQ signal with a gated DQS signal are described. Some aspects are directed to a gating scheme to selectively pass a received strobe signal such as a DQS strobe signal based on a state of a drive enable (DE) signal in a drive circuit in the ATE, such that edges generated by the drive circuit are prevented from mistakenly strobing a received data signal such as a DQ signal.

Abstract: Circuitry and methods of operating the same to delay a signal by a precise and variable amount. One embodiment is directed to a high speed delay line used in automated test equipment. The inventors have recognized and appreciated that an input signal having high data rate may be split into parallel split signals having lower data rates that are delayed in respective parallel delay paths before being combined to generate a delayed signal. One advantage of delaying a signal in such a fashion is to provide high delay line timing accuracy at high data speeds, while using a compact circuit design using circuitry components of lower bandwidth with reduced power consumption, for example by using complementary metal-oxide-semiconductor (CMOS). A further advantage is that a high speed delay line may be constructed from multiple lower data rate parallel delay lines that are modular, simplifying circuit design.

Abstract: Circuitry and methods of operating the same to strobe a DQ signal with a gated DQS signal are described. Some aspects are directed to a gating scheme to selectively pass a received strobe signal such as a DQS strobe signal based on a state of a drive enable (DE) signal in a drive circuit in the ATE, such that edges generated by the drive circuit are prevented from mistakenly strobing a received data signal such as a DQ signal.

Abstract: Disclosed herein are voltage driver circuits and methods of operating the same. In some embodiments, a plurality of circuit slices are provided in a voltage driver circuit, each circuit slice has a time constant, and is controlled to switchably connect a driver output to either a high voltage level or a low voltage level, or to disconnect the driver output from both voltage levels. The circuit slices may provide an adjustable output impedance, which may be set to match the impedance of different loads. The circuit slices may also provide adjustable voltages with low power consumption, particularly in high speed applications. The circuit slices may also have programmable capacitors that may be adjusted to provide a programmable time domain behavior of the output voltage waveform, such as a programmable voltage peaking characteristic.

Abstract: Disclosed herein are voltage driver circuits and methods of operating the same to provide a variable output voltage that is suitable for use in ATE to provide a large number of test signals with accurate voltage levels at high data rates using components that consume relatively low power. According to an aspect, a change in output current in a voltage driver related to changing output voltage may be offset by a stabilization current generated by a correction driver for the voltage driver, such that supply currents drawn from the supply voltages can remain substantially stable. The correction driver may be connected to one or more supply voltages, and programmed to output a stabilization current that offsets changes in supply currents arising from changing of the programmed output of the voltage driver circuit. Such a driver may enable a test system to more precisely test semiconductor devices.

Abstract: Circuitry and methods of operating the same to delay a signal by a precise and variable amount. One embodiment is directed to a high speed delay line used in automated test equipment. The inventors have recognized and appreciated that an input signal having high data rate may be split into parallel split signals having lower data rates that are delayed in respective parallel delay paths before being combined to generate a delayed signal. One advantage of delaying a signal in such a fashion is to provide high delay line timing accuracy at high data speeds, while using a compact circuit design using circuitry components of lower bandwidth with reduced power consumption, for example by using complementary metal-oxide-semiconductor (CMOS). A further advantage is that a high speed delay line may be constructed from multiple lower data rate parallel delay lines that are modular, simplifying circuit design.

Abstract: Disclosed herein are voltage driver circuits and methods of operating the same to provide a variable output voltage that is suitable for use in ATE to provide a large number of test signals with accurate voltage levels at high data rates using components that consume relatively low power. According to an aspect, a change in output current in a voltage driver related to changing output voltage may be offset by a stabilization current generated by a correction driver for the voltage driver, such that supply currents drawn from the supply voltages can remain substantially stable. The correction driver may be connected to one or more supply voltages, and programmed to output a stabilization current that offsets changes in supply currents arising from changing of the programmed output of the voltage driver circuit. Such a driver may enable a test system to more precisely test semiconductor devices.

Abstract: Disclosed herein are voltage driver circuits and methods of operating the same. In some embodiments, a plurality of circuit slices are provided in a voltage driver circuit, each circuit slice has a time constant, and is controlled to switchably connect a driver output to either a high voltage level or a low voltage level, or to disconnect the driver output from both voltage levels. The circuit slices may provide an adjustable output impedance, which may be set to match the impedance of different loads. The circuit slices may also provide adjustable voltages with low power consumption, particularly in high speed applications. The circuit slices may also have programmable capacitors that may be adjusted to provide a programmable time domain behavior of the output voltage waveform, such as a programmable voltage peaking characteristic.

Abstract: Disclosed herein are voltage driver circuits and methods of operating the same. In some embodiments, a plurality of circuit slices are provided in a voltage driver circuit, each circuit slice is controlled to switchably connect a driver output to either a high voltage level or a low voltage level via a resistor, or to disconnect the driver output from both voltage levels. The circuit slices may provide an adjustable output impedance, which may be set to match the impedance of different loads. The circuit slices may also provide adjustable voltages with low power consumption, particularly in high speed applications. A calibration procedure is disclosed herein to generate a lookup table for how to selectively connect circuit slices to supply voltages given a target output voltage.

Abstract: An automatic test system configured for generating a periodic signal of a programmable frequency. The automatic test system may comprise a clock, an edge generator coupled to the clock, a phase locked loop, and a delay adjustment circuit. The edge generator may comprise an edge generator output, an enable input and a delay input. The edge generator may produce at the edge generator output a signal with a delay relative to an edge of the clock specified by a value at the delay input in each cycle of the clock for which the enable input is asserted. The phase locked loop may comprise a reference input and a phase locked loop output configured to provide the periodic signal of the programmable frequency. The delay adjustment circuit may comprise an accumulator that may increase in value by a programmed amount for each cycle of the clock.

Abstract: A semiconductor device-under-test (DUT) may be tested by an automated test system that processes test programs specifying a number of edges per tester cycle that may be greater than the number of edges the tester is capable of generating. The test system may include circuitry that reduces the number of edges in each cycle of a test program based on data specifying operation of the tester in that cycle and/or a prior cycle. Such a reduction simplifies the circuitry required to implement an edge generator by reducing the total number of timing verniers per channel. Nonetheless, flexibility in programming the test system is retained.

Abstract: An automatic test system configured for generating a periodic signal of a programmable frequency. The automatic test system may comprise a clock, an edge generator coupled to the clock, a phase locked loop, and a delay adjustment circuit. The edge generator may comprise an edge generator output, an enable input and a delay input. The edge generator may produce at the edge generator output a signal with a delay relative to an edge of the clock specified by a value at the delay input in each cycle of the clock for which the enable input is asserted. The phase locked loop may comprise a reference input and a phase locked loop output configured to provide the periodic signal of the programmable frequency. The delay adjustment circuit may comprise an accumulator that may increase in value by a programmed amount for each cycle of the clock.

Abstract: Circuitry for measuring a propagation delay in a circuit path. The circuitry includes a one-shot edge triggered element that can be connected in a loop with the circuit path. An edge signal propagating through the circuit path triggers the one-shot element to output a pulse. The pulse propagates around the loop, again triggering the one-shot element to produce a pulse, creating a repeating series of pulses. The period between these pulses is influenced by propagation time of an edge through the loop such that a difference in the period with the circuit path connected and not connected in the loop indicates propagation delay in the circuit path. Such circuitry can be configured to independently measure, and therefore calibrate for, propagation delays associated with rising and falling edges. Calibration to separately equalize propagation delays for rising and falling edges can increase the timing accuracy of an automatic test system.

Abstract: A semiconductor device-under-test (DUT) may be tested by an automated test system that processes test programs specifying a number of edges per tester cycle that may be greater than the number of edges the tester is capable of generating. The test system may include circuitry that reduces the number of edges in each cycle of a test program based on data specifying operation of the tester in that cycle and/or a prior cycle. Such a reduction simplifies the circuitry required to implement an edge generator by reducing the total number of timing verniers per channel. Nonetheless, flexibility in programming the test system is retained.

Abstract: Circuitry for measuring a propagation delay in a circuit path. The circuitry includes a one-shot edge triggered element that can be connected in a loop with the circuit path. An edge signal propagating through the circuit path triggers the one-shot element to output a pulse. The pulse propagates around the loop, again triggering the one-shot element to produce a pulse, creating a repeating series of pulses. The period between these pulses is influenced by propagation time of an edge through the loop such that a difference in the period with the circuit path connected and not connected in the loop indicates propagation delay in the circuit path. Such circuitry can be configured to independently measure, and therefore calibrate for, propagation delays associated with rising and falling edges. Calibration to separately equalize propagation delays for rising and falling edges can increase the timing accuracy of an automatic test system.

Abstract: A robust output buffer component capable of providing high quality output signals comprising a cascode module for receiving a differential signal from a differential pair module and transmitting that differential signal as two output waveforms. Using a bipolar implementation example, the emitter end of a common base cascode pair is coupled to the collector end of a common emitter differential pair with an optional resistive module inserted between the cascode pair and the differential pair. Engineering the cascode bias, the resistance at the collector nodes of the differential pair and/or the resistance at the base nodes of the differential pair effects: the degree of non-linearity of the base-collector capacitance as a function of the base-collector voltage, the voltage swing of the collector nodes, and the degree of symmetry of the input voltages. These three parameters may be used to optimize the symmetry of the output waveforms.

Abstract: An electronic apparatus with a high inductive reactance for differential signals per unit area and a small inductive reactance for common-mode signals relative to its inductive reactance for differential signals with predictable and scalable characteristics. This may be achieved by configuring transmission line pairs such that currents associated with the differential component of a source signal in the first and second transmission lines are aligned and currents associated with the common mode component of a source signal in the first and second transmission lines are counter-aligned. Advantageously, the current invention may be implemented using currently available technology and integrated into a variety of different devices such as broad-band and narrow-band amplifiers, high-speed logic gates, mixers, oscillators, wireless local area networks, global positioning systems and modern communication systems.