Showing papers on "Spice published in 1997"

A new SPICE model of power P-I-N diode based on asymptotic waveform evaluation

Abstract: A new SPICE subcircuit model for power p-i-n diodes is proposed in this paper. The model is based on a moment-matching approximation of the ambipolar diffusion equation. It is shown that both the quasistatic model and the lumped charge model can be obtained as ion-order moment-matching approximations while new and more accurate models can be obtained from higher-order solutions. The proposed model takes into account emitter recombination in the highly doped end regions, conductivity modulation in the base and the moving-boundaries effect during reverse-recovery, showing good convergence properties and fast simulation times. Comparisons between the results of the SPICE model and both numerical device simulations and experimental results are presented.

Delay and Power Expressions for a CMOS Inverter Drivinga Resistive-Capacitive Load

Abstract: A delay and power model of a CMOS inverter driving a resistive-capacitive load is presented. The model is derived from Sakurai‘s alpha-power law and exhibits good accuracy. The model can be used to design and analyze those CMOS inverters that drive a large RC load when considering both speed and power. Expressions are provided for estimating the propagation delay and transition time which exhibit less than 27% discrepancy from SPICE for a wide variety of RC loads. Expressions are also provided for modeling the short-circuit power dissipation of a CMOS inverter driving a resistive-capacitive interconnect line which are accurate to within 15% of SPICE for most practical loads.

A novel RC model of capacitive-loaded parallel and series-parallel resonant DC-DC converters

Abstract: A novel analytical methodology is proposed and applied to investigate the steady-state processes in voltage-fed parallel and series-parallel resonant DC-DC power converters with a capacitive output filter. In this methodology, the rectifier, output capacitor and load are replaced by an equivalent circuit which includes a capacitor and resistor connected in parallel. Excellent agreement was obtained when comparing the numerical values calculated by the proposed model to cycle-by-cycle SPICE simulation and to the numerical results of earlier studies.

An all-purpose transmission-line model for interconnect simulation in SPICE

Abstract: A new all-purpose multiconductor transmission-line model is described for efficient and robust interconnect simulation using nonlinear circuit simulators such as SPICE. All types of interconnects, i.e., uniform, nonuniform, lossless, lossy/dispersive, can be handled by the proposed model. Furthermore, coupling of electromagnetic radiation to interconnects can be directly modeled without the need for developing a new subcircuit. Another advantage of the proposed model is that it enables sensitivity analysis with respect to both circuit and interconnect parameters, thus facilitating interconnect circuit optimization. Chebyshev expansions for the spatial variations of the interconnect voltages and currents are used to effect highly accurate numerical approximations of the Telegrapher's equations using as small a number of degrees of freedom as possible. A simple rule of thumb is provided for the selection of the order of the approximation given the frequency bandwidth of interest. Numerical examples are presented to demonstrate the validity of the proposed model and illustrate its application to a variety of interconnect-induced noise interactions in high-speed electronic systems.

Effects of transistor nonidealities on log-domain filters

Abstract: Log-domain filtering makes explicit use of the diode nature of bipolar transistors to realize log-domain integrators, resulting in coupled translinear circuits. In this paper, the departure from ideal integration due to the major transistor nonidealities is studied, and practical filter deviation equations are derived. The device nonidealities to be tackled include: parasitic emitter resistance, finite beta, base resistance and Early effect. SPICE simulations, both large and small-signal analysis, are performed to verify the results. Compensation schemes are also proposed.

Subthreshold analysis of an MOS analog switch

Abstract: Charge injection error in the presence of subthreshold effects has been analyzed. It is confirmed that the subthreshold effect is significant at low voltage falling rates. A simplified model is derived using an appropriate approximation. Predictions are compared to the results of a SPICE simulation, a nonquasi-static (NQS) model simulation and experimental results. Excellent agreement between the modified and NQS model and recently published experimental results was obtained. This analytical model is computationally efficient compared to the SPICE and NQS models and provides physical insight into the switching errors.

Macromodeling of hysteresis phenomena with SPICE

Abstract: A macromodel for nonlinear devices exhibiting hysteresis is presented. Although this model is based on existing ideas of ferromagnetic hysteresis, it can be applied to all hysteresis phenomena by choosing suitable parameters. It consists only of four algebro-differential equations with ten parameters and exhibits all main features of hysteresis, such as initial curve, saturation, minor loops, coercivity, and remanence. Using standard elements of the widespread simulator SPICE, the macromodel is applicable to all commonly used circuit simulators. It is difficult to extract parameters of nonlinear differential equations from measured values. Therefore, an algorithm for parameter extraction by optimization is presented which is successfully applied to this hysteresis model.

A new approach to extract the threshold voltage of MOSFETs

Abstract: A new method is presented to extract the threshold voltage of MOSFETs. It is developed based on an integral function which is insensitive to the drain and source series resistances of the MOSFETs. The method is tested in the environments of circuit simulator (SPICE), device simulation (MEDICI), and measurements.

A comprehensive submicrometer MOST delay model and its application to CMOS buffers

Abstract: In this paper, an accurate delay model for MOS transistors in submicrometer CMOS digital circuits is presented. It takes into account a ramp shape input voltage and a feedforward capacitive coupling between gate and drain nodes, along with the main second-order effects present in short-channel MOS transistors. The proposed model shows an average agreement with SPICE simulations of 3% in the calculation of the propagation time, tested on a minimum inverter with a 0.7-/spl mu/m CMOS reference technology for a wide range of input voltage slopes. An example of application in optimization algorithms regarding CMOS tapered buffers is also reported. A maximum error ranging from 3-6% with respect to SPICE has been found for the optimized circuits.

Electrothermal modeling of a microbridge gas sensor

Abstract: Fully CMOS-compatible, surface-micromachined polysilicon microbridges have been designed, fabricated, and tested for use in catalytic, calorimetric gas sensing. To improve sensor behavior, extensive electro-thermal modeling efforts were undertaken using SPICE. The validity of the SPICE model was verified comparing its simulated behavior with experiment. Temperature distribution of an electrically heated microbridges was measured using an infrared microscope. Comparisons among the measured distribution, the SPICE simulation, and distributions obtained by analytical methods show that heating at the ends of a microbridges has important implications for device response. Additional comparisons between measured and simulated current-voltage characteristics, as well as transient response, further support the accuracy of the model. A major benefit of electro- thermal modeling with SPICE is the ability to simultaneously simulate the behavior of a device and its control/sensing electronics. Results for the combination of a unique constant-resistance control circuit and microbridges gas sensor are given. Models of in situ techniques for monitoring catalyst deposition are shown to be in agreement with experiment. Finally, simulated chemical response of the detector is compared with the data, and methods of improving response through modifications in bridge geometry are predicted.

SPICE-compatible models for multiconductor transmission lines in Laplace-transform domain

Abstract: Two models for multiconductor transmission lines are presented that are compatible with SPICE. One model is based on a Thevenin equivalent circuit and the other model is based on mode decoupling. The models contain controlled generators in the Laplace-transform domain and are able to handle lossy lines with frequency-dependent parameters.

A scalable, statistical SPICE Gummel-Poon model for SiGe HBTs

Abstract: A scaleable, statistical model has been developed for SiGe HBTs. SPICE Gummel-Poon model parameters are scaled, and statistics added, using language features built into HSPICE. DC and AC fit is good over a wide range in emitter sizes. Features of IBM's HBT technology which make scaling work are discussed.

Implementation of total dose effects in the bipolar junction transistor Gummel-Poon model

Abstract: The effects of total dose on the SPICE model of bipolar junction transistors are investigated. The limitations of the standard Gummel-Poon model for simulating the radiation-induced excess base current are analyzed, and a new model based on an empirical approach is proposed. Four new SPICE rad-parameters are presented, and investigated for different dose rates. The relevant parameters are extracted using a new algorithmic procedure, combining a genetic approach and the standard optimization technique which minimizes the RMS error between measured and simulated excess base current. It is shown that the excess base current is accurately described by the same formula whatever the device type is. An empirical fitting of the rad-parameters as a function of total dose is proposed to use in hardening electronic circuits for space-like environments.

Power p-i-n diode modeling using SPICE

Abstract: A physics based model for the power p-i-n diode is implemented into the general circuit simulation package SPICE. This model based on a variational formulation and finite element solution of the semiconductor equations accurately describes the forward and reverse recovery as well as the conduction behaviour. The procedure used to implement the resulting model into SPICE is described. The simulations are finally compared with known experiments for demonstration of its effectiveness.

Efficient modelling of substrate noise and coupling in mixed-signal SPICE designs

Abstract: Substrate noise in realistically large mixed-signal SPICE designs is in most cases impossible to model directly, owing to inherent instabilities. It is proposed that by modelling only the critical areas of the circuit fast efficient analysis of the substrate noise and its coupling effect on the analogue sections can be performed.

Measurement and simulation of self-heating in SOI CMOS analogue circuits

Abstract: Summary form only given. The influence of dynamic self-heating on SOI MOSFET device behaviour is becoming well known. Although digital circuits typically operate sufficiently fast that self-heating does not affect behaviour, its effects must still be considered during parameter extraction. However, that the operation of analogue circuits will be influenced by self-heating is much more likely. Consequently, SPICE models should include self-heating, with accurately characterised thermal resistances and time constants. This paper explores the effect of self-heating on some common analogue circuits in a 0.7 /spl mu/m PD SOI technology, both from measurements and from SPICE simulations using a new SOI MOSFET model (STAG v2.0).

High performance power MOSFET SPICE macromodel

Abstract: This paper presents a new method of SPICE, behavioral macromodeling of power MOSFETs, that describes device's internal static equations directly with "in line equation" controlled voltage and current sources and the nonlinear interelectrode capacitances are piece-wise-linear approximated with "table defined" controlled sources. The thermal variation of model parameters are equally considered. This new macromodel gives a higher accuracy of static and dynamic power MOSFET description, with no convergence problems and with a reasonable analysis time.

Automatic netlist extraction for measurement-based characterization of off-chip interconnect

Abstract: An approach is presented for modeling board-level, package-level, and multichip module (MCM) substrate-level interconnect circuitry based on measured time-domain reflectometry (TDR) data. The time-domain scattering parameters of a multiport system are used to extract a SPICE netlist from standard elements to match the behavior of the device up to a user-specified cutoff frequency. Linear or nonlinear circuits may be connected to the model ports, and the entire circuit simulated in a standard circuit simulator. Two- and four-port microstrip-circuit examples are characterized, and the simulation results are compared with measured data. Delay, reflection, transmission, and crosstalk are accurately modeled in each case.

SPICE based analysis of radiation from PCBs and related structures

Abstract: SPICE is used to accurately calculate the trace and ground plane currents in PCB structures containing nonlinear circuit elements. Electrical models of the structure are first made using 2D static solvers. When using 2D solvers, a hypothetical reference trace or plane far away is assumed so that imperfections in the ground planes and return paths are accounted for. After the SPICE solution, which includes the nonlinear elements, both common and differential mode radiation are calculated from the currents in the traces, planes and other parts of the structure. While being much faster than full wave EM solvers, this approach can be easily automated using a layout interface. The effect of elements such as EMI filters and of return path currents is also easily calculated.

SPICE electrothermal modeling of power integrated circuits

Abstract: A new analog behavioral modeling method for mixed electrical-thermal SPICE simulations was developed. It can be applied to power integrated circuits as well as to VLSI circuit simulation, where the devices exhibit a dynamic electrothermal behavior. Both the electrical and thermal laws are modeled by means of "in line equation" controlled sources, which form a global electrical equivalent circuit, that can be analyzed with a general purpose circuit simulator. The proposed electrothermal macromodel greatly increases the simulation accuracy and the analysis time is comparable with that of standard intrinsic SPICE models.

Fast time domain simulation in SPICE with frequency domain data

Abstract: The capability of time domain simulation with frequency domain data exists in some time-domain simulators, but the computations can be time-consuming. We decrease this computational burden by exploiting S-parameter fitter and fast recursive convolution methods. With recursive convolution the frequencies at which the S-parameters are sampled may be spaced in any way. For example, a logarithmic frequency spacing allows S-parameters to be sampled over a broader band without increasing the number of frequencies measured. We use two different system identification techniques for extracting the closed-form equations describing measured or simulated S-parameter data. Lumped parameter systems are approximated as a rational polynomial modulated by a complex exponential. Distributed parameter systems are approximated by the sum of complex exponentials. The recursive convolution engine handles both forms. The HP SPICE circuit simulator has been extended to allow fast, recursive convolution methods to be employed for transient analysis. The resulting simulator is called SSpice v2. Significant speed-up in the simulation of several circuits have been achieved using this new technique compared to both the traditional approach in SPICE and our previous direct-convolution-based approach in SSpice v1. In this paper, we present the algorithms and applications of the simulator. Three applications are demonstrated in the paper which are MR head flex line modeling, chip-to-chip signal modeling on MCM, and on-chip inductor modeling.

CMOS adaptive biasing circuits for low-power applications

Abstract: In this paper, a CMOS adaptive biasing topology for low-power applications is presented. The circuit gives an output current which is dependent on the applied input differential voltage. The proposed topology can be utilised in low-voltage low-power operational amplifiers (in particular in their input stages), where a dynamic biasing current helps to save power dissipation. A Spice simulation demonstrating the effectiveness of the proposed solution in a standard 0.7/spl mu/ CMOS technology is also reported.

SPICE modeling of polysilicon thermal actuators

Abstract: This paper reports on modeling the behavior of micromachined polysilicon thermal actuators. The thermal actuators used in this research were fabricated using the DARPA-sponsored multi-user MEMS processes. Data collected in both air and vacuum demonstrates that thermal actuators can be controlled and positioned using a pulsed input with a period much less than the thermal time constant of the device. Both pulse width and pulse amplitude modulation have been successfully employed to position lateral actuators, lateral actuator arrays, and piston micro-mirrors. In order to better exploit the power averaging characteristics of thermal actuators, SPICE models for polysilicon thermal actuators were developed using relationships between resistance, deflection, and average power. These models incorporate the polysilicon thermal actuators electrical load and transient characteristics necessary for predicting actuator performance and developing CMOS drive circuits. The SPICE models exhibit good agreement with theory and measured performance of the polysilicon thermal actuators.

Dose-rate and irradiation temperature dependence of BJT SPICE model rad-parameters

Abstract: A method to predict low dose rate degradation of bipolar transistors using high dose-rate, high temperature irradiation is evaluated, based on an analysis of four new rad-parameters that are introduced in the BJT SPICE model. This improved BJT model describes the radiation-induced excess base current with great accuracy. The low-level values of the rad-parameters are good tools for evaluating the proposed high-temperature test method because of their high sensitivity to radiation-induced degradation.

Parasitic effect removal for analog measurement in P1149.4 environment

Abstract: An intrinsic response extraction algorithm is derived and implemented to remove the parasitic effects in P1149.4 analog measurement. The methodology is tested on and verified by SPICE simulation results and real measurement data.

Effects of floating planes in three-dimensional packaging structures on simultaneous switching noise

Abstract: The effects of floating conductors in three-dimensional (3-D) packaging structures are investigated. The simulations are based on a frequency-dependent integral equation formulation for the calculation of the magnetoquasistatic current distribution in complex interconnect structures. The calculated current distributions are used to develop an inductance/resistance equivalent circuit representation of the package that can be used as a subcircuit in SPICE for simultaneous switching noise calculations. The model is frequency dependent and captures the effect that multiple solid/meshed ground/power planes, pins, vias and traces have on overall package inductive performance. The impact of floating planes, such as a heat spreader under a ball grid array (BGA) structure, on the mutual inductances of the structure is demonstrated. The frequency dependence of the floating plane effects is examined also. The behavior of the induced eddy currents in the floating plane is investigated also, particularly in the vicinity of interconnect discontinuities. Switching noise results obtained using SPICE simulation and the generated inductance/resistance equivalent package models show the effects of floating planes on switching noise.

A new analog behavioral SPICE macromodel of magnetic components

Abstract: A new method of SPICE macromodeling of magnetic components is proposed. It is based on an electric equivalent circuit of electromagnetic laws, where magnetic field intensity and magnetic flux density are simulated with corresponding voltages. The B-H anhysteretic nonlinear curve is piecewise-linear approximated with a "table defined" controlled source, and the hysteresis is introduced with a Schmidt trigger circuit. Using the analog behavioral modeling facilities of modern SPICE type simulators, an accurate and a highly computationally efficient macromodel was developed.

OE-Spice: a CAD tool for design and simulation of OEIC

Abstract: Taking cues from the evolution of the electronic IC technologies, the future development of opto-electronic integrated circuit's (OEICs) needs CAD models and tools, in addition to developing better and more devices. OEUT- Spice was developed to address some of these needs, and to self-consistently treat the electro-opto-thermal interactions between devices, and to become a design and simulation tool for integrated OE circuits. We report on our lab's development over the past few years of this model and some of the effects of the electro-opto-thermal interactions on the devices' performance in the circuit. The implementation of this model in a Spice-compatible format is performed by introducing lumped elements: equivalent optical and thermal capacitors, resistors, and non-linear dependant sources, with sub-circuit dedicated to a key physical mechanism. The result is a CAD tool for design and optimization of OEICs, named University of Toronto Optoelectronics SPICE, or OEUT-Spice. As intended, it can be easily adopted by a very large user group with an electronic IC design background, who are likely to be the future OEICs system designers. To validate the model and extract structure dependent model parameters, we have conducted a number of experiments on lasers, laser arrays and transistors, as well as drawing from experimental results from the literature, and we have consistently obtained good agreements in L-I, I-V, transient responses and emission wavelengths under various temperatures, materials, biases, duty cycles and inter-device spacings. As examples, detailed accounts of results for laser, laser array, and HBT-laser module are presented.

A SPICE model for near-field transient analysis of ferromagnetic grids

Abstract: Ferromagnetic grids are becoming more and more popular for electromagnetic shielding applications in avionics, satellite design, and power electronic systems This paper presents an equivalent homogeneous but anisotropic model of a planar ferromagnetic grid The nonlinear characteristic and the hysteresis of the material are taken into account The field source is a low frequency magnetic dipole placed in the proximity of the grid Both grid and source models are given in the form of multiconductor transmission line (TL) equations They are solved, in the time domain, by the circuit simulator SPICE