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SPICE Designs

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Last Updated: June 02, 2021 01:44 PM

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2nd Gain Stage -  Unfortunately, for particular combinations of slew-rate, first-pole frequency and open-loop gains, the intermediate Op Amp Model just can't handle it.  The spreadsheet coughs up a negative number for RE1 and RE2 making it impractical.  So what's (spice design) __ 

A SPICE Op Amp Macromodel for the LT1012 -  DN28 Design Notes__ Linear Technology/Analog Devices

Active Load in Gain Stage -  instead of a resistor at the transistor's collector, you might have seen a current source (active component) substituted in an audio amp's gain stage.  Why go through the trouble of the added components? You'll find the active loading of a current source packs (spice design) __ 

ADC Input Driver Differential to Differential -  (spice design)  __ Designed by Rick 

Advanced Audio Amplifier -  This is roughly the minimum number of components that represents the classic audio amplifier topology.  You can clearly see the three stages found in many audio amps (and op amps today).  However, looking at actual audio designs, you'll find the basic topology has been tweaked and enhanced in a few key locations (spice design) __ 

Algorithm Overview -  Regardless if you have a great or small interest in understanding how SPIC E works, its a good idea to get a basic grasp of it.  Why? For the same reason it helps to have basic understanding of how your car works, when things go wrong (spice design) __ 

AM Modulator -  This circuit uses two signal generators to simulate an Amplitude Modulated RF carrier wave.  The output can be used to simulate the response of LC and tank circuits.   __ Designed by Andy Collison

An LT1013 & LT1014 Op Amp SPICE Macromodel -  DN12 Design Notes__ Linear Technology/Analog Devices

Analog Behavioral Modeling -  in the good old days, to model a simple LOG function, you reached for a diode from the SPIC E tool shed and embarked on synthesizing the log function.  More complex functions snared you deeper into math and device theory.  You spent more time developing and debugging the math function (spice design) __ 

Analyze LED characteristICs with PSpice -  01/18/01 EDN Design Ideas:  Recent advances in LED technology have lead to LEDs' wideaspread use in outdoor-signal applications, such as in traffic and railroad signals.  A typical LED signal consists of an LED array and a power supply.  When a low-voltage power supply is eir desirable or mandatory, series/parallel combinations of LEDs become inevitable Design by Sam Mollet, GE Harris Harmon Railway Technology, Grain Valley, MO

Audio Tone Controls -  Many people at one time or other, regardless of their interest in electronics, have adjusted these controls to suit their preference.  Whether its to boost the bass of their favorite CD, cut the noise / static on a talk radio station or compensate for poor loud speaker response, they've reached for the treble and bass tone controls.  __ 

Basic Audio Amplifier -  (spice design)  __ Designed by Rick 

Basic Digital Gates -  You're simulating a circuit, it requires several digital gates, but you don't have a mixed-mode simulator.  What to do? One solution involves creating simplified versions of the logic functions.  To do this, we look to the NMOS transistor implementation of logic gates where the transistor acts like a voltage-controlled switch.  But, instead of the transistor, we'll use the SPIC E switch__ 

Basic Op Amp Model -  One of the challenges of simulating OpAmp circuits is modeling the op amp itself.  How is that accomplished? There's a couple of ways.  You can create a circuit of many transistors, resistors and caps that closely replicate the internals of an op amp (spice design) __ 

Behavioral Spice Model Emulates VCO -  07/06/95 EDN Design Ideas:  A behavioral model treats a circuit as a black box, which you can describe using an equation or table.  Listing 1 is a Microsim PSpice behavioral model that simulates the operation of a voltage-controlled oscillator (VCO].  The output signal of a VCO is VO=Aβsin (2„fOt], where A is the amplitude, t is the time variable Design by Dr Bashir Al-Hashimi, Staffordshire University, Stafford, UK

BJT Current Source -  (spice design)  __ Designed by Rick 

Buck Converter-AC Model -  We've already developed a SPIC E model for the Buck Converter in a voltage control loop.  The controller performed brilliantly holding the output steady under varying load conditions.  However, closing the loop is fraught with danger!  Without proper insight, Vo can start ringing and oscillating out of control (spice design) __ 

Capacitor Model -  ideal capacitors exist only in textbooks, not on real circuit boards.  You may be surprised to find that all practical capacitors look (behave) similarly to the series RLC network shown above.  Whether you're designing a filter or picking bypass capacitors, you'll need (spice design) __ 

Capacitor Model Accounts for Temperature, Bias -  01/01/98  EDN Design Ideas:  The basic passive components in Spice are all ideal elements that include no parasitics, such as capacitor ESR and inductor series resistance.  Although it is common to represent a real capacitor with a combination of ESR, equivalent series inductance (ESL) , and nominal capacitance (C) , a more realistic subcircuit representation of a ceramic capacitor takes many more capacitor characteristics into account (Figure 1a).   Design by Debra Horvitz, Galahad Systems, Laguna Hills, CA

Circuit Protects FPGAs from killer Spikes -  04/23/98 EDN Design Ideas:  NOTE: File contains multiple circuits scroll to find this circuit.   A project using Xilinx FPGAs brought an interesting problem to light.  When you turn on the board, one FPGA in three succumbs to this problem.  A lot of frustration and testing uncovered a negative-going spike (Figure 1) in the 5V line from the DC/DC converter.  The system uses a DC/DC converter Design by Nelson Nguyen, Anritsu Corp, Morgan Hill, CA

Circuit Translates TTY Current Loop to RS-232 -  08/01/98 EDN Design Ideas:  (NOTE: Multiple circuits in this file, scroll to find this one.) The circuit in Figure 1a provide as signal translation between a passive current-loop (TTY) interface and a duplex RS-232C port.  The current flowing in the receiver loop causes the transistor to pull down RxD; when the transistor turns off, R1 pulls up RxD.  In like manner, the current in the transmitter loop switches on for a negative TxD voltage and off for a positive voltage.   Design by Jerzy Chrzaszcz, Warsaw University, Poland

Common Emitter Transistor Amplifier -  Hereís a classic circuit thatís still an essential building block of circuits today, both IC and discrete (spice design) __ 

Common-Mode Rejection -  While real op amps do a fantastic job of rejecting voltages common to both inputs, it's not perfect.  A small output results from a change in input common-mode voltage.  What causes this output? Due to mismatching in the transistors and resistors of the input stage, the common-mode voltage produces a small differential error voltage at the input terminals.  Subsequently (spice design) __ 

Compare Spice Simulation to Graphical Template -  11/23/95 EDN Design Ideas:  A former EDN-Design ideas (see Ref 1) described how to use the Laplace-transform feature of PSpice's analog-behavioral-modeling option to compare the simulated frequency response of a circuit with its ideal transfer function.  This approach is useful, provided that you know the circuit's transfer function.  However, you often design circuits, particularly filters, with a frequency response that meets a particular shape in the form of a graphical template.  In this case, you can use another behavioral-modeling feature to plot a given graphical frequency characteristic and compare it with a circuit's simulated response. Design by Bashir Al-Hashimi, School of Engineering, Staffordshire University Stafford, UK

Component Tolerances-Part I -  (spice design)  __ Designed by Rick 

Component Tolerances-Part II -  (spice design)  __ Designed by Rick 

DC Motor Model -  Although SPIC E does not provide explicit models for electro-mechanical devices, like a DC motor, creating one is fairly straightforward.  You just need to remember that most physical behaviors, whether mechanical or electrical, can be described by a set of equations.  So for a desired (spice design) __ 

Delay Line Aids in One-shot Simulations -  EDN Design Ideas:  04/26/01     Many designers use small pulse generators to delay signals, open timing windows, drive sample/hold circuits, and other functions.  Though the hardware implementation of these generators does not pose any problems, the lack of dedicated circuitry sometimes puzzles the Spice simulation of the system.  A common approach to this problem is to implement a time constant involving a resistor, a capacitor, and a comparator.  Unfortunately, each time you need a time constant, you must recalculate the resistor value, the capacitor value, or both.  Despite the fact that inline equations can do this job for you, delay lines can often offer a smarter solution.    Design by Christophe Basso, On Semiconductor, Toulouse, France

Delay line eases Spice Dead-time generation -  03/02/00  EDN Design Ideas:  Generating complementary clock signals in a Spice simulation is an easy task.  However, this task gets much harder if you need to introduce some dead time into the signals.  This difficulty is especially true when you're dealing with a variable-pulse-width- Design by Christophe Basso, On Semiconductor, Toulouse, Cedex, France

Diff Amp with Current Mirror -  in an audio input differential stage, you often see the simple collector resistor replaced with a current mirror.  Why bother? The payoff is two fold.  First, you get twice the gain and current output, typically a good thing for an audio amp.  And second (spice design) __ 

Differential Amplifier -  (spice design)  __ Designed by Rick 

Differentiator -  (spice design)  __ Designed by Rick 

Digital Filter Makes Simple Circuit SPICE Eliminator -  04/10/97 EDN Design Ideas:  As an alternative to counter- and shift-register-based techniques, you can use a digital filter to eliminate spikes from a signal (Figure 1a].  This scheme, which feeds the signal into a digital lowpass filter whose output drives  Design by Francois Corthay Dr Sc, Engineering School Wallis, Switzerland

Driving a Capacitive Load -  You've been warned!  Do not attempt to drive large capacitances with your op amp, severe overshoot and ringing may occur.  But what if you're stuck driving a length of coax cable that's unterminated? You could end up with over 1000 pF that sends the output ringing.  What causes this behavior? Unfortunately (spice design) __ 

Frequency Shaping Stages -  (spice design)  __ Designed by Rick 

Fully Differential Amplifier -  (spice design)  __ Designed by Rick 

H-Bridge Power Amp -  (spice design)  __ Designed by Rick 

Got Designs?
Please eMail
if you want me to link to and/or post your original design Thanks.

Spice:  #'s - L      M - O      P - R      S - Z

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