Published Articles by: Steven C. Hageman
Blog Post - September 2020 - Lowering The Risk In New Designs

Blog Post - September 2020 -
How Common Mode Currents Are Generated in Power Supplies

Blog Post - August 2020 - A different way to USB isolation for low level measurement improvements

Blog Post - July 2020 - YATC - The Yet Another Thermal Camera Project - A fun little Hobby Project

Blog Post - June 2020 -
Thoughts on Ultra Low Noise Audio Preamps

Blog Post - March 2020 - How accurate is that GPS anyway?

Blog Post - September 2019 - Make Your Code More Assertive!

Blog Post - August 2019 - Optimization and the Microchip XC32 Compiler

Blog Post - July 2019 - Bare Metal Programming with PIC32 Processors using Harmony

Blog Post - June 2019 - Do your customers a favor - Make useful Data Plots

Blog Post - June 2019 - Tame that Ringing in Switching Power Supplies

Blog Post - May 2019 - Electronics Design Lifecycle

Blog Post - December 2018 - Make a Simple Low Noise Preamp for Low Frequency Measurements

Blog Post - November 2018 - PIC32MZ/EF Pin Slew Rate Control

Blog Post - June 2018 - Improving Code Quality

Article - January 2018
A Modern DSP Based Lock-In Amplifier designed for Code and Hardware Experimentation. This article is based on a
experimental platform that I designed to facilitate quick hardware and code experimentation.
Down load the article here:
A Modern DSP Based Lock-In Amplifier

Blog Post - December 2017 - Custom 3D printed boxes improve analog designs

Blog Post - December 2017 - The Greatbatch Pacemaker Circuit

Blog Post - Sept 2017 - Friends don't let use un-shielded inductors

Blog Post - August 2017 - Optimizing a FT232R USB / Serial Bridge Throughput Rate

Blog Post - July 2017 - When Microprocessors are a commodity – How do you choose?

Blog Post - March 2017 - Autogenerate C prototype function headers for C

Blog Post - March 2017 - Simple Circuits Add to Versatility of the AD9834 Direct Digital Synthesizer IC

Blog Post - January 2017
Optimizing DFT's with C# Data Types Can a DFT be optimized and does it make sense?

Codeproject - June 2016
Published: DSPLib - A Complete Open Source Library for performing Fourier Transforms on analog signals. All the FFT / DFT
libraries you will find are woefully inadequate for the seemingly simple task of taking in Analog data and producing a usable
Spectrum Plot. DSPLib solves this and gives the user a complete Spectrum Analysis oriented solution for .NET.

Blog Post - April 2016
Find out what happens when a PIC32MZ Microprocessor from Microchip Technology tackles a FFT. These little chips cost less
than a good lunch and pack a really big wallop!

Blog Post - February 2016
Can a DC trace interact with a RF trace when the two aren't even physically connected? You bet they can, a series titled:
"Decoupling RF Circuits" shows one nasty circuit that was betrayed by it's symmetrical beauty.

Blog Post - January 2016
Ever wish you could prototype and simulate your embedded C code on a PC? Well you can with a great free C compiler. Read
about the motivation for this and see a working example here:
Part I, Part II

Blog Post - January 2016
I recently ran across an old article from 1976 written by Jim Williams. The original title was interesting and that question is still
being asked today: "Is Analog Design Dead?"
Read the full Blog Post Here...

EDN October 2015
Read serial data directly into Octave
While Octave will never have the rich and full features of MATLAB, it is possible to read and write serial data to external
instruments and devices, even project boards like the Raspberry Pi and Arduino. Read all about it at the link above.

EDN August 2015
Real Spectrum Analysis with Octave and MATLAB
Ever try to do a FFT Analysis in MATLAB or Octave? Confused by all the totally different and incorrect examples you find? So
was I. This led to the creation of a standard and consistent FFT library for Octave that will handle Signal and Noise Analysis in
a consistent, accurate way. Click the link to read the full article on EDN.

EDN April 2014
Coming soon to a PCB near you
Big advances are coming to PCB layout tools. One of the biggest is integration of mechanical packaging with integrated 3D
modeling and rendering.

EDN March 2014
Beware of the Square Root
This article discusses the scaling errors I find everywhere when FFT's and MATLAB are concerned.

EDN February 2014
GNU Octave hits a high note.
Octave is a OpenSource MATLAB compatible program. With the recent release of a Graphical User Interface it is poised for
some real growth.

EDN January 2014
DSO's and noise
Some things to think about before trying to use a DSO's FFT function to measure noise.

EDN December 2013
DIY Test Equipment
Discusses some DIY Test Equipment that I have made over the years and a few ways to make your own equipment.

EDN October 2013
Long-Lived Design Software
I have been using one software suite since the 1980's. Read more about it.

EDN October 2013
Simple circuits reduce regulator noise
Is even the lowest noise regulator IC still too noisy for your new design? Then these simple "Regulator Cleanup" circuits might
be just the ticket for your next design. As a bonus actual measurements are presented (I think that is a first, as I have never
seen actual measurements of these types of circuits published before).

EDN September 2013
Simple circuit makes flat white noise from 1 to 100 kHz
A simple 12V diode based noise source makes flat white noise from 1 to 100 kHz. The noise source is useful for frequency
response testing and random number generation. The circuit runs off of two 9 V batteries and provides repeatable results
even with a variety of common diodes. Full testing details are presented.

PCB design magazine July 10, 2013
Design for Profitability
Measures for Break Even Time and profitability have been around for ages. This article explains what designers can do to
improve the Profitability of their products by using the tools that they have today to reduce risk and improve cycle time.
Link to magazine download (July 2013 Issue)

EDN July, August and September 2013
Shields are your friend, except when...
Shields used to only really help our high frequency electronic designs, but with frequencies now hovering around 6 GHz on
even consumer electronics they are an integral part of the design because they now interact with the design in ways that
many have not experienced. This three part series details the ins and outs of what can go wrong, some simple calculations to
see if you will have problems and some simple fixes.

EDN, June 4, 2013
Use Fixed Point Math for Embedded Applications
Floating Point Math is just great for programming PC's, but when it comes to Embedded Processors, Fixed Point is far superior
in terms of accuracy, speed and memory footprint. Discusses ways to make the Analog "Fit" in a Fixed Point World.

EDN, March 15, April 9 & May 3, 2013
Low Frequency OPAMP Noise Visualization, Simulation and Practical Considerations
Discusses some of the ways that OPAMP noise may be visualized using a simple spreadsheet. Visualization allows instant
comparison of OPAMP noise between devices and allows the impact on total system noise to be quickly determined. The
series continues with a discussion of how to simulate OPAMP noise and finally some practical OPAMP noise considerations.

EDN, February 6, 2013
"Via spacing on high-performance PCBs"
The Do's and the Don'ts of how to pick a Ground Via spacing for modern High Performance PCBs. With examples, graphs and
an easy to use equation and table and most importantly: What to look for to see if things are OK.

EDN, November 15, December 5, 2012 & January 14,2013
"Use a DVM to Directly Digitize Low Frequency Noise"
A blog post on using the Agilent 34401 DVM as a low frequency noise digitizer. When we think of DVM's we normally think of
measuring just DC signals - modern DVM's can sample really quite fast - Take a look and see what this industry workhorse
has up it's sleeve!
EDN, October 19, 2012
"What PCB material do I need to use for RF?"
A discussion with actual data to help designers faced with some of some of the myths regarding the need for exotic PCB
materials to do RF work up to 6 GHz.

EDN, August 23, 2012
"Measuring Small Signals Accurately: A Practical Guide"
Measuring very small signals close to or even below our instrument's noise floor can be made more accurate by using noise
de-embedding or by applying a multichannel cross-correlation technique.

EDN, June / July 2012
"A trip through quality"
A multi part Blog posting that discusses some lessons learned on what works and what doesn't work on ensuring quality of
our electronic products. Link to the Blog on EDN below
EDN, June / July 2012
"The practicing instrumentation engineer's guide to the DFT"
Discusses practical implementation of the Discrete Fourier Transform in instrumentation applications. The series of articles
focuses on the often forgotten "Calibration" factors and dispels some myths about DFT's and Windowing data in general.
Link to the article at EDN Magazine,

PCB Design 007 March 23, 2012 -  Released as: AnalogHome App Note 005
"Benefits of Coplanar Waveguide Over Ground"
Presents some benefits of using CPWG design techniques for RF PCB Design and some design tips with regard to shielding.
Also see App Note 004 below.

EDN, December 15, 2011
"A few added components make a self-contained controller for 100A load"
The great Jim Williams last article in EDN was on a very wide bandwidth 100A load. Being in the power business for a long
time I have over the years built a number of loads for myself and others also. One thing I have learned from all this is that it is
better to have the controls internal to the load rather than require an external function generator. So using some Linear Tech
parts and a really neat dual LCD DMM module from Lascar Electronics I designed a simple add-on circuit that allows the
Williams load to be controlled with self contained controls.

AnalogHome - App Note 004
"How to make a Low Cost RF Prototype Board that Modern RF Parts Will Actually Fit on!"
A updated and expanded version of the EDN Design Idea Published in 2010. Shows how to make a very good performance
RF board using those one day turn proto-boards that is compatible with surface mount sized parts.

AnalogHome App Note 003
"A program for PCB Estimation with Altium Designer"
A companion article and program for the above PCB Estimator written expressly fro Altium Designer.
The free program can be downloaded here.

PCB Design 007 March 2, 2011
"Estimating PCB Design Time and Complexity"
Describes a free utility program that takes as input your PCB's footprint and quantity information, then outputs a
spreadsheet that gives a measure of the total PCB area utilization and number of pins to be routed. This is a great aid in
understanding the complexity of a new PCB design.
The free program can be downloaded here.

PCB Design 007 January 12, 2011
"Get it 'Right the First Time' With 3D STEP Models"
Altium Designers 3D STEP model import and export capability along with the emergence of many vendor supplied
component STEP models has allowed PCB designers new freedom in the never ending quest to get designs done right the
first time.

EDN, December 15, 2010 (See updated version above - App Note 004)
"Make a quick-turnaround PCB for RF parts"
Shows how to make a very good performance RF board using those one day turn 0.062" thick proto-boards that is
compatible with surface mount sized parts.

EDN, March 1, 2007
"Digital-I/O circuit adapts to many interface voltages"
Faced with the task of designing a universal test fixture that would work with many different logic levels, this circuit makes
use of a 256-tap digital potentiometer to set the interface's voltage via an adjustable regulator between 2.5V and 5V. Kind
of a "poor man's" programmable pin driver.

EDN: March 30, 2006
"Single switch serves dual duty in small, microprocessor-based system"
Ever wonder how to allow a small hand held uP system to be turned on with a pushbutton switch, then be able to turn itself
off? If so then this simple two transistor design is for you. A single pushbutton turns on the uP and also allows another
function to be implemented like changing display modes. Then when the uP is done whatever task it was doing it can turn
itself off. This simple design idea solves this age old problem.

Circuit Cellar Ink: December 2005
"LAN Based Data Acquisition system"
Describes a Data Acquisition system with 8 channels of 12 bit analog I/O (Analog input and Analog Output) and 16
channels of Digital I/O that is fully controllable via a 10/100 Ethernet (LAN) connection. The system talks via an embedded
terminal interface program and can serve up web pages and send email's all via the TCIP protocol. LAN is a very versatile
platform for these kinds of applications as the unit can be programmed anywhere in the world and is not limited to a cable
directly connect to the users PC.

EDN: August 18, 2005, PP84-85
"Frequency Dithering Enhances High-Performance ADCs"
Adding noise (i.e. Dithering) is all the rage with ADCs now a days. Most implementations use random voltage addition to the
ADCs input to dither the ADC. The circuit described uses a random frequency modulation and constant amplitude dither
which has some advantages, especially in FFT applications.

EDN: July 21, 2005, PP70-71
"High Impedance FET Probe Extends RF-Spectrum Analyzers Usable Range"
Basically how to make a 1 Megaohm probe for a 50 ohm spectrum analyzer that has a gain of 1. A useful circuit if you want
to use your 50 ohm spectrum analyzer to probe high impedance circuits.

QST: June, 2004, PP28-34
"Give That Drake Receiver a New Lease on Life"
Modernize that great old Drake R-4 (A, B or C) or SPR-4 series receiver with a PIC controlled synthesizer that gives full 1.5
- 30 MHz receive capability without the need for extra crystals. This project is a modernized Drake FS-4 with a PIC
controlled synthesizer, modern VFD display and many operational features that the FS-4 did not have. Now you can
receive every HF band without the need to shop on ebay for crystals! Reprints of the article are available from the ARRL.

AnalogHome App Note: 002
"Squegging - What is that?"
I have received many questions about what "squegging" is - In this application note, I go over some common forms of
squegging that I know about.

AnalogHome App Note: 001
"Impedance / Frequency Scaling"
I get questions all the time asking: "How do I change this receiver for that band?" or "How do I change that filter from x MHz
to Y MHz?". This brief application note reviews the procedures to 'Tweak' circuits from one frequency or application to
another. Includes a design spreadsheet to speed the calculations and most importantly - what to watch out for.

EDN: February 25, 2004
"Simple technique makes low cost PCB shields"
Describes the process involved to use a small, low cost die-cast aluminum (or zinc) project box as a very effective RF
shield. Pictures show how to layout the ground tracks on the PCB and how to assemble the project box over the PCB.
Since the box has considerable mass it can also be used as a local heatsink for voltage regulators, etc. This technique was
developed for the HF synthesizer project shown in the projects section of this website.

Circuit Cellar Ink: January 2004, PP16-25
"Build an inexpensive temperature-testing chamber"
This project was originally conceived as a way to have a small temperature testing chamber on an engineers bench
without the expense of buying a larger than needed commercial unit. The idea of using a Peltier device to make a small
chamber was in my head for several years - this project came to fruition when a small commercial car travel cooler came
on the market. I added a PIC microcontroller, LCD display, RS232 interface and some power relays - and I was in business!

QEX: March 2002, pp 3-10
"Build a 250 MHz Network Analyzer"
The article shows how to add 8 IC's to the VHF source project (QEX January 2000) to build a true Reflection / Transmission
Network Analyzer. The analyzer is built the same as a commercial design and utilizes a full one port / transmission
calibration routine for outstanding accuracy and performance. The heart of the design is the AD8307 log amp from analog
devices. Reprints of the article are available from the ARRL.

EDN: Dec 20, 2001
"Analog input circuit serves any microcontroller"
This simple A/D converter that can be used with any microprocessor only uses 5 parts and can be built for less than 50
cents. The circuit is based on a simple ramp type architecture, which gives reasonable 5% kind of accuracy. For many
types of "human feedback" the accuracy is more than sufficient especially since the cost is roughly 1/2 of an integrated
circuit A/D converter.

EDN: Nov 22, 2001
"Simple Circuit Forms Peak/Clipping Indicator"
A simple stereo peak detector is presented that is suitable for inclusion in multimedia PC audio applications. The circuit has
easily understood adjustments for gain, attack and delay times.

EDN: Feb 1, 2001, pp 124
"Program predicts VSWR-mismatch RF uncertainties"
Hewlett-Packard (now Agilent Technologies) once offered a useful little cardboard slide rule for calculating the uncertainty
in RF measurements stemming from VSWR (voltage-standing-wave-ratio) mismatch. Unfortunately, this handy device is no
longer available. A Visual Basic program accomplishes the same function on a PC with the added feature of being able to
cut and paste the result, something that the cardboard calculator could not do.
Voted best of issue

QEX: January 2001, pp 52-57
"Build a data acquisition system for your computer"
Introduces the low cost PIC DAS (PIC16C63 Based Data Acquisition System). The PIC DAS is a self contained Data
Acquisition system powered by a PIC Microprocessor. The PIC DAS reads simple ASCII commands from a PC's RS232 port
to control it's 8 bit digital I/O port, 8 channel A/D and 4 channel D/A converters. Also included is full software support for
nearly any computer that can talk to a serial port and any DOS or Windows application. Reprints of the article are available
from the ARRL.

EDN: May 25, 2000, pp 122
"ActiveX control brings bit manipulation to Windows"
I developed this ActiveX control to allow fast 'C' like bit functions to be used with languages like Visual Basic. All the basic
get/set bit and shift functions are included (14 in all). Any Windows language or application that can use ActiveX
technology can use this simple but useful control.

QEX: January 2000 (QEX Cover Project)
"Build this 2-250 MHz VHF Source"
Article describes a hetrodyned VHF source architecture that provides up to +17 dBm output over a frequency range of 2-
250 MHz. The design includes a fast RS232 port for computer control with the capability to have up to four sources 'linked'
on one RS232 port. A PC control program is included along with an ActiveX control to allow nearly any Windows application
to control the source. Reprints of the article are available from the ARRL.

EDN: July 22, 1999, pp 130-132
"Simple Technique Speeds Microstrip Breadboarding"
The title pretty much captures the idea here. By using sheared strips of RT/Duroid PC material and gluing them to regular
FR4 copper clad the development time for making 50 ohm RF circuits can be greatly reduced. Additionally the Duroid
material, since it is Teflon based may be bent conform to whatever shape is needed for the breadboard.
Voted best of issue

EDN: May 27, 1999, pp 104-106
"Use derivatives to catch RF calibration errors"
Describes a method that looks at the time rate of change of a power versus frequency curve instead of just the curve
alone. This shows up things like pinched RF cables and power holes in an easy to see format, whereas with the use of
straight power versus frequency curve, power holes are easily missed during testing of RF components or systems.

QST: March 1999
"PIC Development on a Shoestring"
Chronicles my approach to making PIC microprocessor projects come alive using low cost tools. Includes sections on
selecting PIC's, Writing code in high level languages, Debugging using RS232 and including LCD displays in your projects.
Reprints of the article are available from the ARRL.

QST: February 1999 (QST Cover Project)
"A Synthesized 2 Meter FM Receiver with PC Control"
Built using commonly available IC's this receiver is fully microprocessor controlled. As an added feature the receiver can be
connected to a PC for full computer control. Under PC control the receiver can band scan, do a memory scan and even
display a spectrum of the 2 meter band. Reprints of the article are available from the ARRL.

QST: January (Part I) and February (Part II), 1998 (QST Cover Project)
"Build your own network analyzer"
Using IC's made for the wireless industry I described the hardware and software for a network analyzer that can be built
for personal use. The frequency range is 10 Hz to 16 MHz with a dynamic range of 50-60 dB. The analyzer is run from a
PC via the RS232 port. A complete Visual Basic control program was also presented. Reprints of the article are available
from the ARRL.

EDN: December 18, 1997 pp 102-103
"Metal detector uses single IC"
A simple "beat frequency" type of metal detector is described. The design is based on the LM389 audio amplifier IC using
two of the uncommitted transistors as the search and beat oscillators.
Voted best of issue

EDN: September 25, 1997, pp 170-172
"Single chip builds tiny aircraft receiver"
Why waste time in airports working? Instead build this simple, single chip aircraft band radio and listen in! The unique part of
this circuit is that it uses the Received Signal Strength Indicator (RSSI) of a Philips NE605 as an AM demodulator.
Voted best of issue

EDN: July 17, 1997, pp 112-113
"Opamp makes precise 9V battery splitter"
Describes a circuit to derive a precision 5 volt supply and -4 volt supply from a standard 9 volt battery. Uses a linear Op-
Amp and a precision reference. This circuit is linear, not switching or charge pump.
Voted best of issue

EDN: April 24, 1997, pp 80-81
"Circuit tricks increase LCD contrast"
LCD modules are typically used in single supply embedded projects and they require a negative LCD bias voltage to achieve
maximum contrast. The circuits presented, show simple ways of generating the negative bias by charge-pumping a uP
clock, "stealing" power from a RS232 driver chip and "stealing" negative bias from the RS232 connection directly.

EDN: March 27, 1997, pp 81-83
"Drive high-voltage varactor diodes from just 5V"
Shows a clever way to get 20 volts of drive for a varactor diode from a 5 volt only supply system by using optoelectric

EDN: August 1, 1996, pp 110-113
"Build your own superhetrodyne receiver"
Details the design of a 3 IC short wave radio. The radio covers the 4.5 to 10 MHz band where plenty of international
broadcasters reside. The design includes an RF preselector and ceramic IF interstage filter. Based on a 3 pin Plessy IF amp
/ AM detector IC to reduce parts count.
Voted best of issue

EDN: December 7, 1995, pp 175-181
"Design guidelines help dc/dc converters work properly over long lines"
A common problem in using dc/dc converters in widely distributed systems is how to design the system with respect to the
input resistance that the converter will see. The article shows that the common practice of trying to increase the input
voltage range to greater than 2:1 is fruitless because of the maximum power theorem.

Electronics Specifier: October 1995, Cover, pp 22-23
"Specifying Power Sources"
Covers common sense "Team Design" of power supplies. Although common sense, the steps outlined are not commonly
done. To be a true partner in power system design the entire design and manufacturing team must be willing to partake in
the specification process and review milestones on the go to produce the best products in record time.

Personal Engineering & Instrumentation News: June 1995, pp 50-53
"Models update SPICE to simulate new technologies, circuit types"
Reviews what can be done with SPICE today. Such as simulating batteries, ferrite beads, PCB analysis checking, etc. Also
covers the finer points of modeling passive components for RF frequency effects.

EDN: May 11, 1995, pp 144
"Single IC adds analog inputs to digital PLC"
Shows how to use the single chip RISC Microprocessor from Microchip Technology to add 4 analog inputs to any all digital
Programmable Logic Controller (PLC). The uP is commanded to read any of 4 input channels then it outputs the resulting A/D
code as a series of pulses to the PLC's counter so the PLC can read the result. The number of pulses vary from 0-255
representing the analog input over a range of 0-5 volts.

EDN: February 2, 1995, pp 99
"PSpice models nickel-metal-hydride cells"
An accurate PSpice model is shown that correctly models the discharge of NiMh batteries. The model allows designers the
possibility of running discharge simulations in software for the first time. The model was developed with actual discharge
data, not manufacturers literature, hence the high accuracy.

MicroSim Corp. Newsletter, January 1995, pp 1,8-11
"Use Ferrite Bead Models to Analyze EMI Suppression"
Presents the first universal behavioral models (backed up by actual measurements!) for Ferrite beads. Beads are widely
used for EMI suppression in high speed systems. Until now circuits that used these EMI prevention techniques could not be
simulated. The Bead models take into account the bead material, size of the bead, number of turns and bias current and
accurately predict the frequency response of the bead in circuit.

Electronics Products & Technology: October 1994, pp 84
"Tips on using DC/DC converters"
Reviews the most common user problems and mistakes in applying PCB mount DC/DC converters. Reviews how to properly
add filtering and thermal design considerations.

EDN: October 13, 1994, pp 84
"Serial-Controlled "postage-stamp" computer governs process"
Details the construction and use of a 16 channel to 1 precision analog multiplexer originally designed for ATE equipment.
The Basic Stamp computer takes a serial command to change the mux channel. This easy to build system costs about $100
and compares to systems that cost over $1000.
Voted best of issue

MicroSim Corp. Newsletter, July 1994, pp 8-12
"Model Transient Voltage Suppressor Diodes"
TVS Diodes present modeling challenges to the PSpice user. These diodes are unlike zeners due to their high power
ratings. A complete electrical and thermal model is presented for popular 500 and 1500 watt devices.

EDN: March 31, 1994, pp 59-60
"Low-cost converter drives fluorescent tubes"
Presents a CCFL Tube driver that can be built for less than $3.00. The simple 3 transistor circuit can drive 1/2" by 8" small
tubes at 30 kHz. The input range is 10-20 volts DC. Efficiency is high as total input current is less than 200 mA.
Voted best of issue

PC TECHNIQUES: Apr/May, 1994, pp 84-86
"Exposing the Stealthy Vector-Grabber"
Describes a C language program that will log interrupt-vector usage on a program by program basis. This is useful in
determining if any TSR's could possibly be interfering with other programs. Also let's TSR developers make sure that their
TSR's are working correctly and uninstalling properly.

MicroSim Corp. Newsletter, April 1994, pp 8-12
"Improve Simulation Accuracy When Using Passive Components"
Covers how to model common resistors and capacitors for temperature and frequency dependence. 1/4 Watt Film and SMT
resistors along with leaded and SMT ceramic capacitors are discussed.

EDN: March 3, 1994, pp 96
"Notebook power supply has two outputs"
Describes in detail how to add a simple -24 volt LCD bias output to any forward type of converter. Complete design is given
for a 6-12 volt input, 5 volt @ 1.5 amp and -24 volt @ 10 mA power supply that might be used in a notebook computer or
similar battery operated computer system.

Personal Engineering: March 1994, pp 35-38
"Accurate Transformer Simulation Requires Measuring Key Parameters"
Describes how to apply SPICE's built in "Mutual Coupling" transformer model to real world transformer simulations. Also
describes PSpice enhancements to the standard SPICE transformer model.

PC TECHNIQUES: Feb/Mar, 1994, pp 44-46
"Get That Diskette's Number"
Describes an assembly language subroutine callable from C that will read the volume serial number from a MSDOS 4.0 and
latter formatted disk. Provides a complete assembly listing and C test program.

EDN: Oct 28, 1993, pp 117-132
"Simple PSpice models let you simulate common battery types"
A unified approach to modeling most common battery types is presented. Included are Lead Acid, Nickel Cadmium and
Alkaline types. This article is a first as no unified SPICE models exist for batteries in the public domain. The use of these
models can change a 200+ hour laboratory exercise to a 1 minute computer run.

Electrical Design & Mfg.: Sept/Oct 1993, pp4
"DC/DC Converters Don't Overspecify"
A one page synopsis of the most common ways that users of DC/DC converters can add unnecessary cost to their circuits
that use DC/DC converters. Covers applying the input and output circuits.

MicroSim Corp. Newsletter, October 1993, pp 1 & 3-6
"Create Analog Random Noise Generators for PSpice Simulation"
Reprint of entire text from EDN synopsis above. Program was placed on MicroSim BBS for MicroSim customers to
download. A very popular program and add-on for Pspice.

EDN: May 27, 1993, pp 150
"Program Generates Noise Sources"
Called an "Outstanding Visual Basic Program" by the editors of EDN this program will make PWL random noise sources for
PSpice from your parameters. Calculates and makes models in seconds. Gives noise bandwidth and slewrate of resulting
circuit. A professional application.

CADS (German): January 1993
"Simulation von gemischten Analog/Digitalsystemen"
German version of MicroSim application note, first published in October 1992.

MicroSim Newsletter: October 1992
"Mixed Analog/Digital Simulation Using PSpice"
Gives detailed examples on getting started using the digital simulation capabilities of PSpice. Explains startup conditions,
interfacing to analog circuits and modeling new logic families.

Power Conversion and Intelligent Motion: September 1992, pp 46-52
"Mixed-Mode Simulator Analyzes Switching Supplies"
The PSpice Mixed-Mode simulator is applied to the complete simulation of SMPS power conversion circuits. By modeling the
PWM control chip as a mostly digital device a very fast cycle by cycle simulation can be done Goes into detail on how to
model SMPS chips and getting the simulations to run reliably and quickly.

EDN: May 7, 1992, pp 220
"Spice Models Solar Array"
Complete design equations are given to model a solar panel with Spice. Four simple measurements are made on the solar
array for a complete Spice model.

Electronic Design: March 5, 1992, pp 78
"IC Eases Monitoring of DC/DC Converters"
Designed a simple undervoltage lockout and overtemperature function using one IC that is useful in DC/DC converter circuits.

Electronic Design: May 9, 1991, pp 117&120
"Keep Spice Accuracy Above 1 MHz"
Presents simple macromodels for common 1/4W resistors and 0.1" L.S. Ceramic capacitors that accurately model these
components parasitic components up to 1 GHz. These models greatly improve the accuracy of simulations that exceed 1
MHz or transient time steps of less than 1 uS.

Personal Engineering & Instrumentation News: 1991-1992
Contributing Editor
Served as design automation contributing editor for PE&IN for two years. Wrote 12 columns dealing with selecting EDA
tools, Making EDA work, EDA management and reviewed SPICE and AutoCAD tools and techniques.

EDN: December 20, 1990, pp 154-156
"Spectrum analyzer speeds RMS measurements"
How to use a spectrum analyzer to make wideband rms voltage measurements on complex waveforms. Especially useful
in finding the true heating effect in capacitors, resistors and transistors.

Personal Engineering & Instrumentation News: December 1990, pp 65-66
"PC-based power-supply tester slashes setup time to minutes"
A write-up of the "PC/Workbench" personal power supply tester that was developed at CALEX to provide automated ATE
performance at an engineers desk. Describes hardware configuration, design goals and constraints.

Personal Engineering & Instrumentation News: October 1990, pp 49-56
"Powerful circuit-analysis programs eliminate need for preproduction runs"
Describes the application of Monte-Carlo and Worst Case analysis techniques to find worst case circuit performance.
Describes in detail component modeling and the functional differences between Monte-Carlo and Worst Case analysis
types. Examples are provided using PSpice as a circuit simulator.

EDN: May 24, 1990, pp 173
"Peak detector holds signals indefinitely"
Describes a peak detector - infinite hold circuit that was designed for fast peak charging NICAD batteries. The circuit uses
a Ramp-up D/A technique to capture the peak voltage.

Power Conversion and Intelligent Motion: April 1990, pp 13-24, May
1990 pp 47-50
"Behavioral Modeling and PSpice Simulate SMPS Control Loops"
Behavioral models are applied to switching regulators to produce large signal models that accurately simulate all input and
output characteristics. The models cover voltage mode, feed forward mode, and current mode. Emphasis on simulation
accuracy and avoiding convergence problems.

Electronic Design: March 22, 1990, pp 106
"Rid Measurements Of Supply Noise"
Describes a simple rechargeable/isolated power supply based on NICAD's to supply +/-15 volt power to noise sensitive
circuits. Optically coupled power MOSFETs isolate the NICAD charger during measurements for high isolation, low
capacitance and low noise.

EDN: March 15, 1990, pp 180-181
"Spice models 3-terminal reference"
Presents a SPICE macromodel of the TL431 voltage reference. The model is accurate for most simulations, contains only
one transistor, has no convergence problems and speeds simulation time by at least a factor of 3.

EDN: September 14, 1989, pp 163-164
"Spice Model Handles Linear Optocouplers"
Presents a linearized SPICE model for optocouplers. Model includes input diode characteristics and output transistor
capacitances. If the model is developed for a given operating point very accurate results can be obtained.

EDN: September 1, 1989, pp 117-124
"Proper Output Decoupling Maximizes Power-Supply Operation"
Discusses the dynamic nature (with frequency) of power supply output impedance that all power supplies have. Describes
the potentially devastating effects of adding bypass capacitors to the output of a power supply when the output impedance
is unknown. Proposes measurement techniques and proper bypassing methods.

IEEE: Circuits and Devices Magazine, July 1989, pp 54-55
"Use Modern SPICE Techniques to Analyze Feedback Circuits"
Describes how to make loop measurements on active feedback circuits using SPICE's ideal voltage and current sources.
Overcomes limitations and extends previous methods, resulting in faster computation and smaller net-lists.

EDN: May 11, 1989, pp 197 (Also published in Electronics-World + Wireless-World: Feb, 1992)
"Amplitude-locked loop speeds filter test"
The circuit presented facilitates hands off automatic measurement of a low pass filters cutoff frequency.
Voted best of issue

EDN: November 24, 1988, pp 225
"JFET doubles opto-isolators bandwidth"
Describes the limitations of opto isolators when used in feedback circuits. Presents simple cascode circuits that doubles
the bandwidth of existing designs by adding one JFET.

Electronic Design: November 23, 1988, pp 123-126 and December 14,1989, pp 88.
"Test DC/DC Converters With Isolated Load"
Describes a MOSFET, fully floating, 50 Watt load that is used when testing power supplies. Discusses sources of error
when making measurements and how the load overcomes some of these errors.
Voted best of issue

CADALYST: November, 1988, pp 28-30
"Tailoring AutoCAD: Screen Menus"
Describes in detail how to create custom AutoCAD pull-down menus for user specific applications.

EDN: September 29, 1988, pp 173-182
"Spice techniques facilitate analysis of feedback circuits"
Describes how to make loop measurements on active feedback circuits using SPICE's ideal voltage and current sources.
Overcomes limitations and extends previous methods, resulting in faster computation and smaller net-lists. Describes key
concepts of feedback in detail.

Personal Engineering & Instrumentation News: September 1988, pp 61-72
"Menu/shape system speeds schematic entry with AutoCAD"
Describes a complete ready to use schematic capture system for use with AutoCAD. Provides complete design information
along with shape and menu files.

CADALYST: Vol 5, NO 6, pp 48-50
"Tailoring AutoCAD: Making Shapes"
Describes the thought and coding/compilation process used to define AutoCAD shape files for any custom application.
EDN: June 11, 1987, pp 205
"DC/DC converter adds power to existing bus"
Describes a circuit to add more power to a 5 Volt power bus. Circuit uses another existing supply voltage with excess
capacity and a DC/DC converter.

POWERTECHNIQUES: February 1987, pp 32-37
"DC/DC Converter Serves Diverse Distributed Power Needs"
Describes the CALEX 45 watt, single output family of DC/DC converters. Outlines design features and applications.

Motorola Application Note: AN920A, contributed circuit on page 27
"Theory and applications of the uA78S40 switching regulator"
Describes an Intel EEPROM programming source using the uA78S40 IC.

Power Sources Conference, presented 1984 and 1985
"Modular DC/DC Converter Users Guide"
Conference paper describing uses and DC and high frequency measurement techniques as applied to modular DC/DC

EDN: January 20, 1983, pp 188
"DC/DC converter powers EEPROM's"
Presents a single IC DC/DC converter that will meet Intel EEPROM specifications while working off of an existing 5 Volt bus.
Voted best of issue

Electronic Design: March 31, 1982, pp 105-110
"Program quickly figures complex filter parameters"
An HP-41C application that when given low, high or band-pass filter design goals will prescribe high-pass and low-pass
pole locations to meet the goals. The resulting filter can be realized with active or passive filter sections.

EDN: May 12, 1982, contributed circuit pp 172-174
"Great Gator Giveaway - Winning MUX applications"
Presented a video speed Multiplying DAC design using high speed MUX's and GHz Op-Amps.
Voted first place in the Harris analog design contest

Electronic Design: February 18, 1982, pp 203
"Compensator cancels cold-junction errors"
A circuit is described that uses a single LM-10 Op-Amp to scale and provide for thermocouple cold junction compensation.
Voted best of issue

Electronic Design: January 7, 1982, pp 291-300
"Program analyzes six-element active RC networks"
HP-41C application to find poles/zeros and produce Bode plots of active networks that contain a single Op-Amp and multiple
RC feedback.

EDN: January 5, 1980, pp 166
"Op-Amp Pair forms unity-gain buffer"
An application circuit of how to use a low drift OPAMP connected to the trim terminals of a fast, but not low drift amplifier in a
unity gain application.

Electronic Design: 1980, pp 166 and 400 Ideas For Design, Vol 4, 1980 pp 8, Hayden Book Co.
"BIFET Op-Amp and bipolar Op-Amp join forces for low drift and fast slewing"
Modern application of the classic Goldberg composite amplifier.
Presents a high-performance non-inverting offset nulled composite amplifier.