Showing papers on "Rise time published in 2004"

Ultrafast polarization switching in thin-film ferroelectrics

Abstract: We present an experimental approach to study the ultrafast polarization switching dynamics in thin-film ferroelectrics. A semiconductor photoconductive switch with femtosecond laser illumination is used as a “pulse generator” to produce jitter-free, sub-100 ps rise time step-function-like electrical pulses. Quantitative measurements yield a polarization switching time, ts, of ∼220 ps when measured with a 5 V, 68 ps rise time input electrical pulse. Modeling of the switching transients using the Merz–Ishibashi model and Merz–Shur model of switching kinetics yields a quantitative estimate of the characteristic switching time constant, t0, of ∼70–90 ps.

Coherent dynamics of a Josephson charge qubit

Abstract: We have fabricated a Josephson charge qubit by capacitively coupling a single-Cooper-pair box (SCB) to an electrometer based upon a single-electron transistor (SET) configured for radio-frequency readout (rf-SET). Charge quantization of 2e is observed and microwave spectroscopy is used to extract the Josephson and charging energies of the box. We perform coherent manipulation of the SCB by using very fast dc pulses and observe quantum oscillations in time of the charge that persist to ≃10 ns. The observed contrast of the oscillations is high and agrees with that expected from the finite EJ/EC ratio and finite rise time of the dc pulses. In addition, we are able to demonstrate nearly 100% initial charge state polarization. We also present a method to determine the relaxation time T1 when it is shorter than the measurement time

Off-diagonal impedance in amorphous wires and its application to linear magnetic sensors

Abstract: We investigated the magnetic-field behavior of the off-diagonal impedance in Co-based amorphous wires under sinusoidal (50 MHz) and pulsed (5 ns rise time) current excitations. For comparison, we measured the field characteristics of the diagonal impedance as well. In general, when an alternating current is applied to a magnetic wire, the voltage signal is generated not only across the wire but also in a pickup coil wound on it. These voltages are related to the diagonal and off-diagonal impedances, respectively. We demonstrate that these impedances have a different behavior as functions of axial magnetic field: the diagonal impedance is symmetrical, whereas the off-diagonal one is antisymmetrical with a near-linear portion within a certain field interval. For the off-diagonal response, the dc bias current is necessary to eliminate circular domains. In the case of the sinusoidal excitation without a dc bias current, the off-diagonal response is very small and irregular. In contrast, the pulsed excitation, combining both high- and low-frequency harmonics, produces the off-diagonal voltage response without additional biasing. This behavior is ideal for a practical sensor circuit design. We discuss the principles of operation of a linear magnetic sensor based on a complementary metal-oxide-semiconductor transistor circuit.

Disk drive estimating angular position of spindle motor during spin-up by computing differences in winding current rise times

Abstract: A disk drive is disclosed comprising a spindle motor having a plurality of windings including at least a first winding, a second winding, and a third winding. During a spin-up operation, a voltage is applied to the first winding and a first rise time is measured for current flowing through the first winding to reach a predetermined threshold. A voltage is applied to the second winding and a second rise time is measured for current flowing through the second winding to reach a predetermined threshold. A voltage is applied to the third winding and a third rise time is measured for current flowing through the third winding to reach a predetermined threshold. A difference is computed in response to the first rise time, the second rise time, and the third rise time, and an angular position of the spindle motor is estimated by computing an arctangent in response to the difference.

Characterization of human Metal ESD reference discharge event and correlation of generator parameters to failure levels-part I: reference event

Abstract: Electrostatic discharge (ESD) generators are used for testing the robustness of electronics toward ESD. Most generators are built in accordance with the IEC 61000-4-2 specifications. Using only a few parameters, this standard specifies the peak current, the rise time and the falling edge. Lacking a transient field specification, test results vary depending on which generator is used, even if the currents are quite similar. Such a specification is needed to improve the test repeatability. As for the current, the specification should be based on a reference human metal ESD event. While keeping the presently set peak current and rise time values, such a reference ESD (5 kV, 850-/spl mu/m arc length) is identified and specifications for current derivative, fields, and induced voltages are derived. The reference event parameters are compared to typical ESD generators.

An offset compensation technique for latch type sense amplifiers in high-speed low-power SRAMs

Abstract: The input referred offset voltage occurring in the full latch V/sub DD/ biased sense amplifier has been analyzed extensively. The process variations in the matched nMOS and pMOS transistors have been accounted by /spl plusmn/2.5% variation in V/sub T/ and /spl plusmn/5% variation in /spl beta/, from typical values. Effect of various design parameters on the sense amplifier offset has been studied and reported. It has been shown that the rise time of the sense amplifier enable signal (SAEN) has a profound effect on the offset voltage. The slower transition of SAEN signal is proposed to result in high speed as well as low-power consumption in SRAM application. An analytical model has been derived for simplified latch to model the effect of rise time of SAEN signal on offset voltage.

Plasma source with segmented magnetron cathode

Abstract: A sputtering apparatus includes a chamber, an anode, a cathode assembly comprising target material, and a magnet. A platen supports a substrate. A power supply is electrically connected to the cathode assembly and generates a plurality of voltage pulse trains comprising at least a first and a second voltage pulse train. The first voltage pulse train generates a first discharge that causes sputtering of a first layer of target material having properties that are determined by at least one of a peak amplitude, a rise time, and a duration of pulses in the first voltage pulse train. The second voltage pulse train generates a second discharge from the feed gas that causes sputtering of a second layer of target material having properties that are determined by at least one of a peak amplitude, a rise time, and a duration of pulses in the second voltage pulse train.

Model-based controller design for machine tool direct feed drives

Abstract: This paper presents a controller design methodology for machine tool direct feed drives. The methodology is applied to a linear motor (LM) and a piezoelectric actuator (PA). The structure of each plant model is obtained from physical laws and its parameters are obtained using system identification. A single transfer function (TF) model is shown to accurately predict the response of the LM. For the PA, multiple local models are required to accurately represent its dynamics. Next, a procedure for designing a model-based two degrees-of-freedom (2DOF) controller with anti-windup protection is presented for the single model and multiple model cases. With the LM, friction compensation, force ripple compensation and a disturbance observer are added to improve the tracking performance. Experimental results for both drives are included for step, ramp and sinusoidal reference inputs. For the LM, the rise time for a 1000 μm step input is reduced from 25 to 3.5 ms in comparison to a proportional-integral-derivative (PID) controller. For the PA, the rise time for a 10 μm step is reduced from 6 to 1.5 ms.

Pulsed wave interconnect

Abstract: Pulsed wave interconnect is proposed for global interconnect applications. Signals are represented by localized wave-packets that propagate along the interconnect lines at the local speed of light to trigger the receivers. Energy consumption is reduced through charging up only part of the interconnect lines and using the voltage doubling property of the receiver gate capacitances. In a 0.18-/spl mu/m CMOS technology case study, SPICE simulations show that pulsed wave interconnect can save up to 50% of energy and /spl sim/30% of chip area in comparison with the repeater insertion method. A proposed signal splitting structure provides reasonable isolations between different receivers. Measured S-parameters of 3.8-mm interconnect lines fabricated through CMOS foundry showed that the distortion and attenuation of a pico second signal are much less serious than the theoretical predictions. Pulsed wave interconnect also enables time division application of a single line to boost its bit rate capacity. The use of nonlinear transmission lines (NLTL) is also proposed to overcome pulse broadening and attenuation caused by dispersion and frequency-dependent losses. Pulsed waves on an NLTL may be generated, transmitted, split and detected with components realizable in bulk and SOI CMOS technologies. Tapered NLTL can be used for pulse compression. NLTL edge sharpening abilities may be applicable for signal rise time control.

Picosecond response of gallium-nitride metal-semiconductor-metal photodetectors

Abstract: Metal–semiconductor–metal ultraviolet photodiodes fabricated on GaN were tested in the picosecond regime with an electro-optic sampling system. A device with a feature size of 1 μm showed a response with 1.4 ps rise time and 3.5 ps full width at half maximum. The derived electron velocity, 1.43×107 cm/s, is in good agreement with independent photoexcitation measurements. A slower impulse response was observed in a device with smaller feature size of 0.5 μm.

Analysis of shock wave measurements in water by a piezoelectric pressure probe

Abstract: Investigation of underwater electrical wire explosions occurring in the time scale of few microseconds requires a measurement of pressure waves with nanosecond rise time and microsecond fall time. Various types of pressure gauges are used for this purpose, however, none of them seems to be suitable for the task since the frequency range of the pressure waves lies between 107 and 109 Hz, whereas all types of mechanical gauges have a bandwidth below 107 Hz. Therefore, a mathematical processing of measurements is required for reconstruction of the actual pressure wave forms. In this article, a signal processing algorithm, based on energy conservation requirements and Fourier analysis, for reconstruction of the wave form of the pressure wave generated under water by electrical explosion of wires is proposed. The gauge used in the experiments is a PCB 119A12 type pressure gauge with a bandwidth below 1 MHz produced by Piezo-Electronics, Inc. Pressure waves were produced by underwater electrical explosion of a thin wire made of Cu by a current pulse with an amplitude of 30–60 kA having a rise time of a 3 μs. It is shown that the error of the gauge in the measurement of the peak pressure is more than 100%, which leads to an error in the estimation of the energy of almost 300%.

Performance of a wideband (3-14 GHz) dual-pol array

Abstract: A test array of 25/spl times/25 dual-pol flared dipoles ("bunny-ears") was built and tested. It was designed for 3-14 GHz applications with a low profile (1.2 cm thick). The egg-crate radiating aperture can be integrated with a thin radome and the multi-layer feed to form a load-bearing structure of an airborne platform. The array has an instantaneous bandwidth of 10 GHz, manifested by an impulse response with 100 ps rise time. Smooth well-behaved "active" element patterns in the E-, H-, and diagonal plane were observed. Cross-pol components were typically 30 dB below the co-pol at broadside and 20 dB on average at 60 degree off axis. Element gain over the band was measured and the data tracked fairly well with the theoretical curve defined by the element's unit area gain (4/spl pi/A//spl lambda//sup 2/).

Compact submicrosecond, high current generator for wire explosion experiments

Abstract: The PIAF generator was designed for low total energy and high energy density experiments with liners, X-pinch or fiber Z-pinch loads. These studies are of interest for such applications as surface and material science, microscopy of biological specimens, lithography of x-ray sensitive resists, and x-ray backlighting of pulsed-power plasmas. The generator is based on an RLC circuit that includes six NWL 180 nF–50 kV capacitors that store up to 1.3 kJ. The capacitors are connected in parallel to a single multispark switch designed to operate at atmospheric pressure. The switch allows reaching a time delay between the trigger pulse and the current pulse of less than 80 ns and has jitter of 6 ns. The total inductance without a load compartment was optimized to be as low as 16 nH, which leads to extremely low impedance of ∼0.12 Ω. A 40 kV initial voltage provides 250 kA maximum current in a 6 nH inductive load with a 180 ns current rise time. PIAF has dimensions of 660×660×490 mm and weight of less than 100 kg...

High gain-bandwidth differential distributed InP D-HBT driver amplifiers with large (11.3 V/sub pp/) output swing at 40 Gb/s

Abstract: High-performance and compact 40-Gb/s driver amplifiers were realized in 1.2-/spl mu/m emitter double-heterojunction InGaAs-InP HBT (D-HBT) technology with a maximum cut-off frequency (f/sub T/) of 150 GHz and a maximum oscillation frequency (f/sub max/) of 200 GHz. Two-stage differential drivers feature a lumped input and fully distributed output stage and deliver a maximum differential output swing of 11.3 V peak-to-peak (V/sub pp/) at 40 Gb/s with less then 350 fs of added rms jitter and rise and fall times of about 7 ps while consuming a total power of 3 W. When biased at a lower output swing of 6.3 V/sub pp/, excellent 40-Gb/s eyes with a 7-ps fall time, 6-ps rise time, and no observable jitter deterioration compared with the input source are obtained at a reduced power consumption of 1.7 W. On-wafer measured differential S-parameters show a differential gain of 25 dB, 50 GHz bandwidth, and input and output reflection below -20 dB from 2 to 45 GHz. The amplifiers' small die size (1.0/spl times/1.7 mm), relatively low power consumption, large output swing, and ability to have dc coupled inputs and outputs enable compact 40-Gb/s optical transmitters with good eye opening for both conventional transmission formats such as nonreturn-to-zero and return-to-zero and alternative formats such as duobinary and differential phase shift keying.

Closed-loop independent DLL-controlled rise/fall time control circuit

Abstract: A system and method for processing signals determines rise and fall times of a driving signal, compares the rise and fall times to desired values, and independently controls the rise and fall times to equal the desired values. The rise and fall times may be controlled by generating one or more first correction bits based on a difference between the rise time and a corresponding one of the desired values, generating one or more second correction bits based on a difference between the fall time and a corresponding one of the desired values, and then separately applying the bits to independently control the rise and fall times of the driving signal. The driving signal may be an I/O signal or another type of signal.

Evaluation of energy consumption in RC ladder circuits driven by a ramp input

Abstract: In this paper, the energy consumption of RC ladder networks, which can represent chains of transmission gate or long wire interconnections, is modeled. Their energy dependence on the input rise time is analyzed by assuming a ramp input waveform. Since the analysis can be carried out in a straightforward manner only for very simple RC ladder networks, the exact analysis is first limited to asymptotic values of the input rise time T (i.e., for T/spl rarr/0 and T/spl rarr//spl infin/). Successively, the energy expression is extended to arbitrary values of the input rise time by introducing a suitable equivalent first-order RC circuit, whose resistance and capacitance are simply related to the resistances and capacitances of the original network. The energy expression found is useful for pencil-and-paper evaluation and affords an intuitive understanding of the network dissipation, since each term has an evident physical meaning. By comparison with SPICE simulations, the energy expression proposed is showed to be accurate enough for modeling purposes.

Truly balanced step recovery diode pulse generator with single power supply

Abstract: A space efficient and simple circuit for ultra wideband (UWB) balanced pulse generation is presented. The pulse generator uses a single step recovery diode to provide a truly balanced output. The diode biasing is integrated with the switching circuitry to improve the compactness of the design. Two versions of the circuit with lumped and distributed pulse forming networks have been tested. The pulse parameters for distributed pulse shaping network were: rise/fall time (10-90%) 183 ps, pulse width (50-50%) 340 ps, pulse peak to peak voltage 896 mV (12.05 dBm peak power) and for the lumped case: rise time (10-90%) 272 ps, fall time (90-10%) 566 ps pulse width (50-50%) 511 ps, pulse amplitude /spl plusmn/1.6V (17 dBm peak power). In both cases excellent balance of the two pulses at the output ports can be observed. It should be noted that above parameters were obtained with typical inexpensive RF components. The circuit reduces the complexity of the design because of the lack of broadband baluns required for UWB balanced antennas. The circuit may be used as part of a UWB transmitter.

Optimal design of clock trees for multigigahertz applications

Abstract: With the onset of gigahertz frequencies on clocked digital systems, inductance effects become significant. We investigate appropriate regimes where signal propagation on an IC can be characterized as resulting from transmission line (TL) behavior. The signals propagate at a speed in the proximity of the speed of light in the medium. Our starting points are exact solutions in the time domain to the TL equations. A methodology to evaluate the feasible domains of physical and electrical variables that permit TL propagation is given. We develop fast and accurate computational methods for inductance and capacitance calculations. A general expression of the time delay in the presence of finite rise time and finite load capacitance for TL propagation is derived. We analyze a clock-synthesis method based on sandwiched balanced H-trees consistent with TL propagation. We find the feasible physical domains by solving iteratively two nonlinear equations in a space spanned by two continuous variables, with four parameters. To further assert its applicability we remove common assumptions such as the constancy of the electromagnetic parameters, zero rise time, and load capacitance. The spectrum of configurations is satisfactory at 130 nm and scales well into the 45-nm generation.

Erratum to “A Fast Digital Filter Algorithm for Gamma-Ray Spectroscopy With Double-Exponential Decaying Scintillators”

Abstract: Scintillators like CsI(Na), having double-exponential decay times, typically cannot be used in high-count rate applications due to the complicated pulse shapes created by the convolution of their light output decay curves with the decay constant of charge integrating preamplifiers. We present here a novel digital filtering algorithm that is capable of using CsI(Na) at input count rates exceeding 250 kcps, while still achieving good energy resolution. We used a 2.54 cm diameter and 2.54 cm long CsI(Na) crystal, whose scintillation light can be best described by a short component with a 550 ns decay time and a long component with a 4 /spl mu/s decay time. The crystal was coupled to a 2.86 cm diameter photomultiplier tube. The digital filtering algorithm was implemented in XIA's all-digital Polaris spectrometer, in which five running sums were captured from each digitized scintillation pulse and the Polaris's on-board DSP read these sums and used a set of precomputed coefficients to reconstruct the pulse's total light output as a measure of the deposited energy. The algorithm was tested at different input count rates, ranging from 19 kcps to 270 kcps using a 1 mCi /sup 137/Cs source. The energy resolution (full-width at half-maximum) at 662 keV was 10.7% at 19 kcps and 11.7% at 270 kcps with a filter rise time of 1.0 /spl mu/s, and improved to 7.0% and 8.4%, respectively, with a filter rise time of 3.2 /spl mu/s. The energy peak shifted by less than 0.3% for input count rates below the maximum throughput point. Output count rates of 65.3 and 17.8 kcps were obtained with filter rise time of 1.0 and 3.2 /spl mu/s, respectively, at an input count rate of 270 kcps. This algorithm can be easily adapted to other double-exponential decaying scintillators by changing the decay times used in the energy reconstruction formula.

High-speed large-area surface-normal multiple quantum well modulators

Abstract: Since 1998, the Naval Research Laboratory has been developing modulating retro-reflectors (MRR) for free-space optical (FSO) communication links. Using an MRR is beneficial for asymmetric links containing one node with weight or power constraints, such as ground-to-air links. An MRR configuration shifts most of the power, weight, and pointing requirements onto one node. To close an MRR link at any significant distance, the area of the modulator must be fairly large. Using a large area limits the data rate, since capacitance is proportional to area. Resistance also depends on device size, although not in the same manner. To increase the data rate, we designed a top metal contact that diminishes the effect of the semiconductor resistivity. Using this new top contact design decreases the rise time from approximately 2.6 μs to 60 ns using the same wafer structure. However, increasing the data rate increases the power input and results in self-heating, which changes the optimal operating wavelength of MQW modulators. Accordingly, a new coupled quantum well structure is designed. The new design lowers the required drive voltage, which in turn lowers the power consumption, increases yield, and simplifies drive circuitry. The lower power input also reduces the modulation rate dependence of the wavelength.

Improved wafer-level VFTLP system and investigation of device turn-on effects

Abstract: We present an improved wafer-level VFTLP measurement system. This system produces pulses with sub-150 ps rise time and few distortions at the rising edge. By introducing a broadband power divider, the oscilloscope no longer limits the pulse amplitude, and arbitrarily high pulse voltages can be measured. Turn-on effects in diodes and NMOSFETs are investigated using this system.

Evaluation of dynamic performance of pressure sensors using a pressure square-like wave generator

Abstract: In this study, we measured the dynamic characteristics of pressure sensors using a pressure square-like wave generator (PSWG). With high excitation energy, the PSWG can measure dynamic pressure and work more effectively in a high frequency range. Under the same experimental parameters (10 bar, 600 Hz), the performance of six pressure sensors of dissimilar design and structure was evaluated. The experimental results indicate that they all exhibited extremely different dynamic characteristics. The dynamic pressure sensors based on quartz plates and crystals possess larger overshoot, greater gain margin and shorter rise time in comparison with other sensors based on strain gauge and piezoresistive materials. Compared with other traditional methods, such as the hydraulic control method, the PSWG proves to be superior in that it can be employed to evaluate the dynamic performances of pressure sensors at high frequency of above 10 kHz.

Transparent monitoring of rise time using asynchronous amplitude histograms in optical transmission systems

Abstract: This paper describes the analysis, simulations, and proof-of-principle experiment on transparent monitoring of relative rise time using asynchronously sampled amplitude histograms in optical transmission systems. The method described is based on the count in a selected amplitude window between the mark and space levels. The method is evaluated under various amplitude windows and Q-factor values and is compared with synchronously sampled eye-diagram-based measurements. The results demonstrate that the 40-60% amplitude window is generally suitable for system rise-time monitoring purposes without clock information.

EMI reduction by optimizing the output voltage rise time and fail time in high-frequency soft-switching converters

Abstract: In order to ensure the compatibility between devices, several electromagnetic compatibility (EMC) standards specify the maximum permitted levels of radiated noise. To comply with these standards, hard switching power converters need to use expensive solutions, namely shielding, Filtering techniques and snubbers, because the voltages have low values of rise and fall times. This fact leads into significant harmonic content at high frequencies. In this case, the most cost effective way to deal with radiated noise is to reduce it at the source. A way to achieve this goal is to impose moderate values of output voltage rise and fall times. This paper theoretically and experimentally explains, that the harmonic content at high frequencies can be significantly reduced with a selection of a suitable value of voltage rise time and fall time. Based on the study of a generic trapezoidal waveform, simple but precise equations, that permit to easily evaluate the envelope of the frequency spectrum, are derived. These equations also permit to analyze the importance and the influence of the rise and fall times in the spectrum envelope. Finally, with this simple analysis, the influence of the values of rise time and fall time in more complex waveforms are shown, as the output voltage waveform of a high frequency cycloconverter. The validity of the theoretical analysis is confirmed by experimental results.

Current scaling of radiated power for 40-mm diameter single wire arrays on Z

Abstract: In order to estimate the radiated power that can be expected from the next-generation Z-pinch driver such as ZR at 28 MA, current-scaling experiments have been conducted on the 20 MA driver Z. We report on the current scaling of single 40 mm diameter tungsten 240 wire arrays with a fixed 110 ns implosion time. The wire diameter is decreased in proportion to the load current. Reducing the charge voltage on the Marx banks reduces the load current. On one shot, firing only three of the four levels of the Z machine further reduced the load current. The radiated energy scaled as the current squared as expected but the radiated power scaled as the current to the 3.52±0.42 power due to increased x-ray pulse width at lower current. As the current is reduced, the rise time of the x-ray pulse increases and at the lowest current value of 10.4 MA, a shoulder appears on the leading edge of the x-ray pulse. In order to determine the nature of the plasma producing the leading edge of the x-ray pulse at low currents furt...

Portable system for measuring dynamic pressure in situ and method of employment therefor

Abstract: A dynamic pressure testing or calibration system packaged as a portable unit for characterizing pressure sensors, such as transducers. Embodiments are packaged for carry on the body, are battery-operated, compatible with existing transducer mounts, and quickly learned and easily used by a single operator. The system supplies a pre-specified impulse (pressure pulse) of fluid, preferably a benign gas, such as air, or an inert gas such as helium or nitrogen. In select embodiments, the gas pulse has a fast rise time and its amplitude may be varied over a pre-specified dynamic range. For example, the rise time may emulate that of an impulse created during an explosion by a resultant pressure wave, i.e., less than 100 microseconds. Embodiments also incorporate a data acquisition capability that accurately captures and records both the supplied impulse and the response of the sensor under test.

Computation of signal-threshold crossing times directly from higher order moments

Abstract: This paper introduces a simple method for calculating the times at which any signal crosses a prespecified threshold voltage (e.g., 10%, 20%, 50%, etc.) directly from the moments. The method can use higher order moments to asymptotically improve the accuracy of the estimated crossing times. This technique bypasses the steps involved in calculating poles and residues to obtain time-domain information. Once q moments are calculated, only 2q, multiplications and (q-1) additions are required to determine any threshold-crossing time at a vermin node. Moreover, this technique avoids other problem such as pole instability. The final outcome of this paper is a set of empirical expressions relating the moments to different threshold-crossing times in analogy to the t/sub d/=-0.693m/sub 1/ formula. The presented methodology can also be used with other user defined forms of empirical expressions relating the moments to different threshold-crossing times. Several orders of approximations an presented for different threshold-crossing times, depending on the number of moments involved. For example, the worst-case error of a first- to seventh-order (single to seven moments) approximation of 50% RC delay is 1650%, 192.26%, 11.31%, 3.37%, 2.57%, 2.56%, and 1.43%, respectively. This technique is very useful to obtain information about certain signal metrics, such as delay and rise time directly without having to compute the whole time domain waveform. In addition, if the whole waveform is required it can be easily determined by interpolation between different threshold-crossing points. The presented technique works for both step and nonstep inputs, including piecewise-linear waveforms.

Investigation of circuit-level oxide degradation and its effect on CMOS inverter operation and MOSFET characteristics

Abstract: Circuit-level oxide degradation effects on CMOS inverter circuit operation and individual MOSFET behavior is investigated. Individual PMOSFET and NMOSFET devices are assembled off-wafer in the inverter configuration through a switch matrix. A range of gate oxide degradation mechanisms are induced by applying a ramped voltage stress (RVS) of various magnitudes to the input of the inverter. A novel circuit model is used to simulate the voltage transfer curves (VTCs) of degraded inverters. At the transistor level, increased gate leakage currents of nearly eight orders of magnitude are observed, in addition to severely reduced on-currents (> 50 percent reduction), and large threshold voltage (V/sub th/) shifts (> 100 mV). At the circuit-level, stress of either polarity results in inverter performance degradation. For the DC characteristics, oxide degradation attributed to limited hard breakdown (LHBD) in the NMOSFET and hard breakdown (HBD) in the PMOSFET, results in decreased output voltage swing (> 260 mV). Under the same conditions, inverter degradation in the voltage-time (V-t) domain exposes much larger changes in performance. For instance, significant increase in the rise time results in the output voltage being pulled up to only 660 MV (V/sub DD/ = 1.8 V) before switching low. From a circuit reliability viewpoint, it may be possible for subsequent circuit stages to compensate for a few degraded devices, but in highspeed circuits, increased rise/fall and delay times may cause timing issues. Furthermore, increased gate or off-state leakage currents can potentially load previous circuit stages or result in increased power consumption.