SPICE modeling of process variation using location depth corner models

For robust designs, the influence of process variations has to be considered during circuit simulation. We propose a nonparametric statistical method to find sets of simulation parameters that cover the process spread with a minimum number of simulation runs. Process corners are determined from e-test parameter vectors using a location depth algorithm. The e-test corner vectors are then transformed to SPICE parameter vectors by a linear mapping. A special corner extension algorithm makes the resulting simulation setup robust against moderate process shifts while preserving the underlying correlation structure. To be applicable in a production and circuit design environment, the models are integrated into an automated model generation flow for usage within a design-framework. The statistical methods are validated for analog/mixed-signal benchmark circuits.     

One-dimensional modeling of TE devices considering temperature-dependent parameters using SPICE

Based on simplified one-dimensional steady-state analysis of thermoelectric phenomena and on analogies between thermal and electrical domains, we propose both lumped and distributed parameter electrical models for thermoelectric devices. A couple of important advantages of the presented models are that the temperature dependence of material properties is considered and that they can be easily simulated using an electronic simulation tool such as SPICE. For a single free-standing pellet, comparisons are made between SPICE simulations using the proposed models and with numerical simulations carried out with Mathematica software. Results illustrate accuracy of the distributed parameter models and show how inappropriate it is to assume, in some cases, constant material parameters for an entire thermoelectric element.     

The electrothermal macromodel of voltage mode PWM controllers for SPICE

In the paper the problem of modelling PWM voltage mode controllers for SPICE is considered. SPICE library isothermal macromodel and a new form of the authors' electrothermal (including selfheating) macromodel of SG3525A controller are presented and compared. To illustrate the correctness and usefulness of these macromodels, some results of measurements and calculations of SG3525A controller operating in the catalogue test circuit and in the real BOOST converter are given as well.     

Early effect modeling in SPICE

The approximations made in the Early effect formulation of the SPICE Gummel-Poon bipolar junction transistor (BJT) model were reasonable when the model was first developed but introduce unnecessary inaccuracies when modeling the output conductance of modern BJTs. In this paper, we give the reason the original approximations were made, present a new way to plot data to best show the Early effect, and detail a new, consistent, coupled method to determine forward and reverse Early voltages     

通用电容传声器动态特性模型的建立与SPICE仿真

运用电一力一声类比的方法,建立通用电容传声器的集总参数等效电路模型,并采用SPICE软件对电容传声器的动态特性进行计算机仿真和优化。     

Non-linear average electrothermal models of buck and boost converters for SPICE

The new method of formulating non-linear average electrothermal models of dc-dc converters is presented in the paper. These models take into account both: non-linearity of diode and transistor characteristics and electrical inertia of these elements. The form of the models for buck and boost converters is presented and their correctness is verified by comparing the characteristics of the considered converters obtained with the proposed model and the classic transient analysis.     

可变R-L-C元件的SPICE模拟行为建模

一些仿真器没有包含LRC元件的ABM方程,采用本文所述的简单子电路,可以根据复杂的分析表达式（包括逻辑表达式）创建无源元件,比如建立非线性电容、时变电阻等.     

Simulating oscillators using SPICE

SPICE generation of the output signals from electronic oscillator circuits is obtained by transient analysis. Simulation success is software specific and depends upon how the transient analysis function is configured. Different tricks, which are oscillator configuration specific, may be applied to achieve simulation output. In the final analysis, one must remember that simulation is not a complete and full replacement for circuit construction and testing. Accurate analysis is given for resonant or relaxation circuits     

A SPICE modeling technique for GaAs MESFET IC's

A vertically integrated device modeling technique for GaAs IC's is presented for use in circuit simulation. Most of the SPICE2 capability can be utilized for modeling the gate transit time and parasitic effects. A computer program has also been developed to extract model parameters from the measured device data.     

Applications of SPICE for modeling miniaturized biomedical sensor systems

This paper proposes a model for a miniaturized signal conditioning system for biopotential and ion-selective electrode arrays. The system consists of three main components: sensors, interconnections, and signal conditioning chip. The model for this system is based on SPICE. Transmission-line based equivalent circuits are used to represent the sensors, lumped resistance-capacitance circuits describe the interconnections, and a model for the signal conditioning chip is extracted from its layout. A system for measurements of biopotentials and ionic activities can be miniaturized and optimized for cardiovascular applications based on the development of an integrated SPICE system model of its electrochemical, interconnection, and electronic components.     

Electrically controllable all-fiber PMD emulator using a compact array of thin-film microheaters

An electrically controllable, all-fiber polarization-mode dispersion (PMD) emulator is constructed using thin-film microheaters to temperature tune the birefringence of 30 PM-fiber sections spliced at 45/spl deg/ angles. Compact packaging is achieved by mounting the fiber heaters onto an array of silicon V-grooves. The advantages of this electrically tunable emulator design are low loss, negligible PDL, simple construction, no internal reflections, and no moving parts.     

Fast simulation of sigma-delta modulators using SPICE

Presents a fast simulation method using SPICE. We traded the prohibitive time-consuming simulation problem for a much less time-consuming problem, plus a little analysis work. This makes it possible for one to use SPICE simulation to optimize the parameters in the modulator within a reasonable time period. Rounding and truncation errors within the circuit simulation algorithms typically set an upper limit on the measurable SNR on the order of 90 dB. This implies that very high-resolution modulators cannot correctly be simulated by SPICE. Fortunately, 90 dB resolution is adequate for most modern communication baseband A/D converters     

A new approach to the modeling of converters for SPICE simulation

An approach to the modeling of DC-DC converters for SPICE simulation is developed in which the average current in the energy-storage inductor is first simulated in a SPICE subcircuit for both the continuous and discontinuous modes of operation. The inductor current is then weighted and redistributed to related branches of the circuit to simulate the average input and output currents of the converter. Based on this technique, various converter models, including that of the Cuk converter with coupled inductors, which are valid for both continuous and discontinuous modes of operation, are developed     

Fully integrated electrothermal multidomain modeling of RF MEMS switches

RF MEMS switches have demonstrated excellent performance. However, before such switches can be fully implemented, they must demonstrate high reliability and robust power-handling capability. Numerical simulation is a vital part of design to meet these goals. This paper demonstrates a fully integrated electrothermal model of an RF MEMS switch which solves for RF current and switch temperature. The results show that the beam temperature increases with either higher input power or increased frequency. The simulation data are used to predict switch failure due to temperature-related creep and self pull-in over a wide range of operating frequency (0.1-40 GHz) and power input (0-10 W). Self pull-in is found to be the dominant failure mechanism for an example geometry.     

Design metal-dot based QCA circuits using SPICE model

This paper proposes a SPICE model development methodology for quantum-dot cellular automata (QCA) cells and presents a SPICE model for QCA cells. The model is validated by simulating the basic logic gates such as inverter and majority voter. The proposed model makes it possible to design and simulate QCA combinational circuits and hybrid circuits of QCA and other NANO devices using SPICE. In the second half part of the paper, SET and QCA co-design methodology is proposed and SET is used as a readout interface of the QCA cell array. The SET and QCA hybrid circuit is a promising nano-scale solution.     

Simulation and modeling-the macro modeling of phase locked loopsfor the SPICE simulator

A modeling approach that uses no semiconductor junctions and no regenerative feedback is described. The voltage-controlled oscillator is implemented by means of a circuit producing essentially infinite ringing, and the comparator characteristics are obtained by means of an odd-order polynomial transfer function. The design of the comparator, phase detector, low-pass filter, and error amplifier are also discussed. Performance of the complete macro-model is such that 8000-point simulations, corresponding to some 150 cycles of local oscillator, can be performed in about 15 min on a platform such as the Sun 3/60, or Apollo DN4500     

SPICE模拟纳米技术场效应晶体管圆角效应的建模技术

This paper presents a novel poly(PC)and active(RX)corner rounding modeling approach to SPICE simulations.A set of specially designed structures was used for measurement data collection.PC and RX corner rounding equations have been derived based on an assumption that the corner rounding area is a fragment of a circle.The equations were modified to reflect the gouging effect of physical silicon wafers.The modified general equations were implemented in the SPICE model to enable the model to describe the corner rounding effect.The good fittings between the SPICE model simulation results and the silicon data demonstrated in this paper proved that the designed corner rounding model is practical and accurate.     

Failure mechanism and SPICE modeling of AlGaAs/GaAs HBT long-term current instability

The long-term current instability of AlGaAs/GaAs heterojunction bipolar transistor (HBT) is studied, and the physical mechanism contributing to such a behavior is investigated. Based on this, a model capable of predicting the HBT long-term current drift and mean time to failure (MTTF) is developed. In addition, such a model is implemented into SPICE circuit simulator, thus allowing the simulation of HBT circuits subjected to an electrical and thermal stress condition.     

Coupled package-device modeling for microelectromechanical systems

Microelectromechanical systems (MEMS), by their nature as sensors and actuators, require application specific packaging. The package is the near environment of the MEMS device and hence has a direct effect on its thermal behavior, mechanical effects, environmental compatibility and contamination. Therefore, understanding the influence of the packaging on MEMS device performance is critical to a successfully coupled package-device co-design. Here, an automated package-device interaction simulator has been developed. The simulator uses separate finite element method models for both the package and the device analysis and ties the simulations together through parametric behavioral package models. This technique allows the generation of package model libraries and supports the co-design of application specific packaging and MEMS devices. In the current implementation, thermomechanical package models have been implemented. Experimental verification of the technique is demonstrated by the comparison of simulation results to the measured package strain data. Although MEMS device-package interactions are not the only systems that could benefit from this method, they are a significant application area, focused on here.     

Analysis, optimization, and SPICE modeling of resonant cavity enhanced p-i-n photodetector

We present a detailed analysis, optimization, and SPICE modeling of the resonant-cavity-enhanced p-i-n photodetector (RCE-p-i-n-PD). Time response, frequency response, and the quality factor of RCE-p-i-n-PD are calculated for different thicknesses of the active layer and for different areas of the photodetector. The standing-wave effect is examined for all these calculations. The effect of the parasitic inductor is studied, and then an optimization is applied to the photodetector to get the optimal value of thickness of the active layer and the series inductor values. Two cases are compared, one with an inductor (L) in series with the load resistor (R/sub L/), and another without this inductor. High performance is obtained in the first case with an inductor, and its optimal values are obtained. A SPICE model for this high-speed photodetector is also presented, and the transfer function of this model is compared for different parameters of the device. Finally, predictions from this SPICE model are compared with published experimental results.