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Application Report
SLOA029 - October 1999
1
THS4001 SPICE Model Performance
James Karki
ABSTRACT
This document outlines the SPICE model of the THS4001 high-speed monolithic operational
amplifier. General information about the model file structure, performance comparison,
model listing, and a brief comment about symbols are included. The listing can be copied and
pasted into an ASCII editor, or it can be down loaded by visiting the THS4001 product folder
at http://www.ti.com/sc/docs/products/analog/ths4001.html.
Contents
1 Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 File Structure 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Performance 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Schematic and Subcircuit Listing 8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 Subcircuit Listing 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Note About Building a Symbol 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Introduction
SPICE modeling has become commonplace today, especially with the advent of affordable PCs
with computing power that surpasses the mainframes of yesteryear.
A major concern in SPICE modeling is the accuracy of the models. Without a good model,
simulation results are not much more than verification of rudimentary circuit operation. The
Boyle op amp model, introduced during the mid ‘70s, did not need a lot of computing resources
and provided reasonable results for the µA741. Since its introduction the Boyle model has been
enhanced to add more accuracy.
Today, full transistor models simulate with speed and accuracy on modest home systems. The
goal, when creating the SPICE model of the THS4001 high-speed monolithic operational
amplifier, is to provide a model that will accurately simulate the actual device in a circuit. The
model is derived from the full transistor model used internally by TI design. Simplifications are
made to speed simulation time and various performance parameters are adjusted to match the
model to measured device performance.
2 File Structure
The THS4001 SPICE model file, THS4001.lib, is written in ASCII file format and is compatible
with a wide variety of computing platforms. The model is written in subcircuit format and has
been tested with MicroSim
PSpice
release 8 and OrCAD PSpice
version 9. It should be
compatible with most SPICE2 and SPICE3 based simulation programs.
