About AIM-Spice

Introduction

SPICE is the most commonly used analog circuit simulator today and is enormously important for the electronics industry. SPICE is a general purpose analog simulator which contains models for most circuit elements and can handle complex nonlinear circuits. The simulator can calculate dc operating points, perform transient analyses, locate poles and zeros for different kinds of transfer functions, find the small signal frequency response, small signal transfer functions, small signal sensitivities, and perform Fourier, noise, and distortion analyses.

The simulator was developed at the University of California, Berkeley, and was first released in 1972. Many scientists at Berkeley and other institutions contributed to the development and improvement in subsequent versions of SPICE. In 1975, Nagel described the next major release of SPICE, called SPICE2. The core of the program still remained intact, even after many improvements and additions. These included improved device models, numerical techniques, and user interfaces. The last major release, SPICE3, came in 1985 with a conversion of the source code from FORTRAN to the C programming language. The Berkeley version of SPICE is a public domain program, but since the late 1970s a number of companies have released commercial versions of SPICE, providing further improvements in user support, in user interfaces, and, in certain cases, also in models and in simulation convergence.

AIM-Spice is a new version of SPICE running under the Microsoft Windows operating systems, including Windows 3.1, Windows 98, Windows NT, Windows 2000 and Windows XP. One of the immediate benefits is that AIM-Spice is capable of displaying graphically the results of a simulation in progress, a feature that allows the operator to terminate a run based on an instant information on intermediate simulation results. The development of AIM-Spice was motivated by the need of a more user friendly interface, and as a vehicle for the new set of advanced device models for circuit simulation developed by our group.

AIM-Spice Features

	AIM-Spice runs on the Microsoft Windows operating system family.
	Uses the Berkeley SPICE version 3.E1 as the kernel.
	Displays simulation results in progress by plotting graphically circuit variables during a run.
	Includes advanced new models for a number of semiconductor devices.
	Includes a graphical post processor, AIM-Postprocessor.

User Interface

In choosing Microsoft Windows as the operating environment we have the following advantages compared to the DOS environment:

A more user friendly interface: Microsoft Windows has a common user interface. This means that when you learn to work with one application, you learn at the same time how to work with all of them. Microsoft Windows also has a graphic user interface (GUI) which allows for a more visual mode of working.

More Available Memory: Microsoft Windows takes full advantage of the memory installed in the computer above the 640K DOS limit. This permits the simulation of large circuits.

Multitasking: Microsoft Windows offers a multitasking environment. This means that it is possible to start a simulation and then switch to another application for other tasks, such as post-processing of a previous simulation.

Simulation Control

In AIM-Spice the operator has complete control during a simulation. Before a simulation starts, the circuit variables to be monitored during the run are selected, and AIM-Spice will display graphically the progress of these variables during the simulation. The figure below shows a typical snapshot of an AIM-Spice simulation in progress.

New Semiconductor Device Models

New advanced models for the following semiconductor devices are implemented in AIM-Spice:

Heterostructure Diode

Heterojunction Bipolar Transistor (HBT)

MOSFETs. The following MOSFET models are included:

Level 1,2, 3 and 6 from Berkeley

BSIM1

BSIM2

BSIM3v2

BSIM3v3.1

BSIM3v3.2

BSIM3 SOI

BSIM4 versions 1.0, 2.0 and 2.1

GaAs MESFETs and HFETs.

Amorphous Silicon Thin Film Transistors (a-Si TFTs)

Polysilicon Thin Film Transistors (poly-Si TFTs)

The FET models are all based on versions of the unified charge control model (UCCM), which describes the channel charge in Field Effect Transistors (FETs) in the above and below threshold regimes, using one analytical expression.

New Features in Version 3

	Temperature sweep analysis
	Support for libraries
	Libraries containing thousands of devices
	Support for parameters in the netlist
	Support for parameters in subcircuit calls
	Polynomial dependent sources (POLY sources)
	Global nodes
	BSIM3 versions 2 and 3 ((MOSFET levels 13 and 14)
	Enhanced commenting features (comment blocks and comments within continuation lines)

AIM-Postprocessor

A graphic postprocessor is included in the AIM-Spice simulator package. This application, like AIM-Spice, runs under the Microsoft Windows environment.

Although AIM-Spice has facilities to plot circuit variables graphically, AIM-Postprocessor has a much more powerful plotting engine including the following features:

Plotting of sums and differences, derivatives, integrals, and mathematical functions of circuit variables and creating hard copies.

FFT (Fast Fourier Transform)

Cursors to select numerical values and to calculate differences between variables.

Import of experimental data.

Hard copies

More Information

More information on AIM-Spice can be found in the following two books:

T. A. Fjeldly, T. Ytterdal, and M. Shur, Introduction to Device Modeling and Circuit Simulation, John Wiley & Sons, New York, (1998), ISBN 0-471-15778-3.

K. Lee, M. Shur, T. A. Fjeldly, and T. Ytterdal, Semiconductor Device Modeling for VLSI, Prentice Hall, Englewood Cliffs, NJ (1993), ISBN 0-13-805656-0. This book is in the Prentice Hall "Available on Demand program". YOU CAN ONLY ORDER IT THROUGH A COLLEGE BOOKSTORE of your choice.When ordering it from Prentice hall, please specify TITLE CODE : 805655.

Buy the books online at Barnes&Noble by clicking here.

Last modified on February 03, 2002