Analog Innovations

Device Models, & Subcircuits  10-BIT DAC (Behavioral) Subcircuit (with PSpice & LTspice Symbols)

When you are designing a system at the device level (transistors, resistors, etc.), it's convenient (and speedy) to represent some subsystems behaviorally while you wring out other system components, e.g. a successive approximation register.  Thus I threw this 10-Bit DAC behavioral model together... trivial actually, but saved me tons of time.  I have now made this a fully parameterized subcircuit with VFS (full-scale-output), VH (high logic level) and VL (low logic level) selectable by the user.   A Set of Symbols that Output Digital 16-Bits Broadside, Steps or Pulses, for PSpice

This Set of PSpice Symbols allows simulation of Analog circuits that need Digital Addressing (up to 16-Bits).

The first symbol, 16-Bit-Step, allows parametric analysis.  You input a parameter "Decimal" which is converted by the subcircuit to the binary equivalent.  All Bits are available as True and Complement, and levels VH (high, volts) and VL (low, volts) are settable from the schematic.

The second symbol, 16-Bit-Gen, is a 16-Bit Wide Pulse Generator.  User selectable parameters are TB (bit time, seconds), TRF (rise and fall times, seconds), VH (high level, volts), VL (low level, volts), and StartNumber (the decimal number that the generator starts at... not yet functional, bug discovered ;-).  All Bits are available as True and Complement.    Rudimentary Behavioral Model of Analog Devices AD633 Analog Multiplier, now with LTspice Symbol. 

Noise, CMRR and Feed-Thru are not modeled.   Updated with improved output swing bounding (8/14/2014).    LTspice Library and Symbol for Analog Devices AD790 Fast, Precision Comparator.

This is a totally behavioral model based upon datasheet information only.  Please report any issues via the Envelope Icon on the home page of this site... Comments _most_welcome_!  (It is recommended that the LTspice Alternate Solver be used.)    In need of an AD834 Spice Model for an off-the-shelf consulting project and the ADI model I found on the web was "not an official release", I rolled my own.

LTspice _only_ for now.  Reposted 1/25/2015 including noiseless R model, and LTspice symbol.  Comments most welcome, I want to get these sort of animals modeled correctly.    AD8218  Current Shunt Monitor, high side sensing, behaviorally-modeled subcircuit, now with LTspice Symbol.

My re-write of ADI's model, correcting mismatches between performance and data sheet.  This is a work-in-progress, and has limitiations:  Input bias currents are a guesstimate based on the data sheet; transient response timing is symmetrical (until I update my Op-Amp-Config, see link below); Input-referred noise and Output current limit are not yet modeled.  Comments and corrections are welcomed.    Spice Model for the Analog Devices ADCMP551 Single-Supply High Speed PECL/LVPECL Comparator.  Comments and suggestions welcome. Updated 6/26/2017.    Spice Model for Analog Device ADG788 Quad Analog Switch.  SWAG from Datasheet.   Please test and report any issues.    Apex Microtechnology's ( low quiescent current, high power dissipation operational amplifier that integrates several new layers of onboard circuit protection including over current shut down.  Onboard temperature monitoring circuitry, also new, enables the MP118FD to shut down the system before any permanent damage can occur.   The product is compatible with supplies up to 200V, is capable of 10A of continuous output current, or 12A PEAK, and has a power bandwidth of 140kHz.  Circuit protection functions fully behavioral modeled, amplifier circuitry modeled at device-level (for now :-)   Now with LTspice Symbol.    Behavioral Differential Pairs, Improved/Updated 7/17/2015 (Serious Bug Fixed ;-)  Transition width (10-90%) parameterized.  With LTspice Symbols.

BasicOpAmpOutputStage.png    Basic OpAmp Output Stage... Passes Load Current to Proper Voltage Rail... No Voltage Bounds, No Current Limit, Yet ;-)    Two Behaviorally Modeled Comparators... One push-pull output, one equivalent to open drain/collector.  Delay Time and Transition Width (and Sink Current for OD/OC) are parameterized.    Circuits that Limit and/or Control the Routing of Input Voltages.   Device-Level Spice Models for some aged parts, but still in many a junk box.   Spice Modeling the temperature and voltage effects in common capacitors.

CD4007_SPICE_MODEL.pdf   Spice Model for NMOS and PMOS FET's in the CD4007 Chip, Courtesy of Dr. Lynn Fuller, Rochester Institute of Technology.   DC, F and G Current Sources with Definable Voltage Compliance Limits... in other words, real-world behavior.  UPDATED!  4/15/2015, now includes subcircuit representation library.   Test your circuit designs in Spice with a current-limited power supply.  D-to-A and A-to-D Interface Subcircuits (with PSpice Symbols)

Depending on the amount of Probe Data in PSpice, you are generally limited to around 10-11 plots per Probe window.  I recently encountered difficulties while trying to display the successive approximation bit sequence of a 10-bit A-to-D converter I was designing.  So I developed the  Parts contained in to allow converting device-level voltages (Analog) to Digital representation, and, likewise, Digital Stimuli to Analog Stimuli.  UPDATED!  Preliminary Spice Library of the Basic Logic Elements, INVerter, BUFfer, NAND, AND, NOR, & OR... BEHAVIORAL.

Changing Direction... defining Input Pins to have the requisite delays (and hysteresis).  Combinational Outputs to be added.

These digital primitives (behavioral) take as input conventional analog voltage signals, thus can be simulated on most Analog Simulators.  Inputs are Analog 0 to 1V and Outputs are also Analog, 0 to 1V.   Propagation delay is parameterized.  To match physical parts, I/O cells will be added to model pin capacitances, CPD (dissipation capacitance parameter). and overall propagation and transition times, and voltage swing versus load capacitance.  Watch this space.

Now with LTspice Symbols.

FauxMOSFET.pdf   A purely mathematical behavioral model of a MOSFET...

With all derivatives continuous, suitable for modeling logic elements that can be run in an Analog simulator environment.  Turns out to be a nice "faux" FET, but way more complex than needed for Logic Functions... see beginnings of Digital Behavioral Modeling at the "" entry, just above, for a better approach.   FUNCTION GENERATOR/VCO

Updated 30 December 2016.  Function Generator that you can independently set maximum frequency, FMAX, at control voltage VMAX, minimum frequency, FMIN, at control voltage VMIN.  This subcircuit features Triangle, Square and Sine-Wave Outputs.  This device is useable from DC to approximately 1GHZ.

GD16_TABLE_vs_TANH_Limiting.pdf   Comparison of behavioral modeling techniques: TABLE versus TANH; and resulting derivatives and discontinuities.   Device-Level Spice Model for the venerable 74HCU04 Unbuffered Inverter.   Two Spice Models for the VCO Portion of the 74HC4046 PLL Chip, One Entirely Behavioral, One Mostly Device-Level.  Updated 09/08/2014.

Includes the original posting of the device-level model in an LTspice schematic.  Added: HC4046_VCO_BEH.lib, a much simpler approach.   Universal Spice Model for the HC4538 One-Shot. 

Most simulators have their own proprietary way of modeling digital blocks... they don't work on any other simulator.  This Spice Model uses behavioral modeling that simulates digital functions on ANY simulator.

See above.   Behavioral Spice Model of a Generalized Hysteresis Element.   Spice Model for an incandescent lamp.  Handy for estimating turn-on surge-current behavior and sizing drivers appropriately.   Spice Model for a saturating inductor.  Good match to lab measurements.  Does not yet have hysteresis (coming soon :-)   Programmable Input-Referred Noise Voltage & Current Sources for Amplifier Noise Modeling.  (Updated 08/18/2014)  LM339 Comparator Subcircuit (Partially Behavioral)  LM361 High Speed Differential Comparator Subcircuit (Totally Behavioral) plus LTspice Symbol.   Please report any issues/comments.  Subcircuit model for the whole TI LM4040 Precision Micropower Shunt Voltage Reference Family.  Added 10/28/2016:  Subcircuit call/instantiation by part number.

LM94022_SUBCKT.pdf  LM94022 Multi-Gain Analog Temperature Sensor with Class-AB Output (Behavioral)  Spice Model of the venerable Motorola Monolithic IF Amplifier.  Device-level, so it's accurate... however package parasitics are parameterized.  Spice Model of the venerable Multiplier/Modulator/Demodulator.  Device-level, so it's accurate.  Behavioral Spice Model for Logic Level Shifter MC14504 (Also CD4504).  Behavioral Spice Model for Universal Voltage Monitor MC33161.  This is a SWAG based ONLY on the datasheet.  Please report any issues via the Envelope Icon on the Analog Innovations Home Page.  Behavioral Spice Model for Microchip OpAmp MCP6001. 

Updated 2016/11/21 with improved swing limiting and a more realistic output stage. This is a SWAG based ONLY on the datasheet.  Please report any issues via the Envelope Icon on the Analog Innovations Home Page.  Behavioral Spice Models for Microchip Miniature Single-Cell (ALL 32 options are modeled :-), Fully Integrated Li-Ion, Li-Polymer Charge Maintenance Controllers.

This is a SWAG based ONLY on the datasheet.  Please report any issues via the Envelope Icon on the Analog Innovations Home Page.  Behavioral Spice Models of the Microchip MCP656x Comparator Chips.

Developed following posts on the LTspice List that Convergence problems were encountered with the Microchip-provided Spice model.  This is a first pass and doesn't cover all specifications.  Please report any issues via the Envelope Icon on the Analog Innovations Home Page.  Behavioral Model for the venerable DIAC Trigger for TRIAC's and SCR's.  Please report any issues via the Envelope Icon on the Analog Innovations Home Page.  LMC555 CMOS Timer Subcircuit (Mostly CMOS Device Level, Partially Behavioral)    Need a resistor in your .AC/Noise Analysis that doesn't add noise of its own?   This behavioral equivalent does just that.   CONFIGURABLE OP-AMP SYMBOL for PSpice

This PSpice Symbol/Model is a CONFIGURABLE can independently set DC Gain, Gain-Bandwidth, Slew-Rate, Open-Loop Output Resistance, Positive and Negative Swing Limits, and Phase Margin.  This Device is Behavioral Modeled and features 90 degrees phase after the low frequency corner... until excess phase sets in, exhibiting Phase Margin of PM° at 0dB Open-Loop Gain.    Thus your simulations will be much more accurate than those obtained with just an E-Source.  (The subcircuit can be used in most other Spice variants.)

PotentiometerForSpice.pdf   Parametrically Variable Potentiometer Subcircuit (with PSpice Symbol)

A parametrically variable potentiometer symbol (self-contained subcircuit) for PSpice.  Import into the symbol library of your choice or make into a subcircuit for other Spice variants.  (The file is text.)  Parameters are VALUE (end-to-end resistance) and SET (wiper set-point fraction of full scale).   Device-Level Spice Models of my original mid-'60's serial port driver/receiver chip designs.

SubcircuitImportByNetlist.pdf   Import clients' chip information into your schematic without having to manually reproduce their device-level drawings.  Many symbol samples.   Subcircuit Symbol Library for Use with PSpice Schematics

A set of subcircuit symbols from 1-pin to 16-pins, plus some 8, 14, and 16-pin symbols to match package numbering.   My SWAG/Approximation to Microchip's 9A High-speed MOSFET Drivers.  A lot of this is pure guess-work... IMNSHO the TC4421/TC4422 Datasheet has to qualify as one of the worst... pages and pages of pretty much useless curves.  Also, IMNSHO, the Spice model that Microchip distributes is a nasty subterfuge, guaranteed to cause convergence issues... containing fully 25 Table functions for each device :-(  Thus my SWAG to see if I can get it to function with LTspice.  I have not included my usual power-up portions... not enough data available to model it.  As usual, comments, suggestions, complaints are welcome... use the envelope icon on the home page.   Behavioral Spice Model for the ST "10W car radio audio amplifier".  As with many models here, this is a work in progress.  Comments welcome.   Behavioral Spice Models for some old, but still used, OpAmps.

TL431_Spice_Models.pdf   Subcircuit equivalency for the TL431 Shunt Regulator, with Subcircuit Spice models from several manufacturers.   Behavioral Spice Model of the TI TL598 Pulse-Width-Modulation Control Circuits.   Derived only from Datasheet and ApNote.  LTspice symbol.

TLP191B_Subcircuit.pdf   Subcircuit model for the Toshiba TLP191B Photocoupler.  Obsolete but amusing to test my curve fitting abilities >:-}    Updated development of the behavioral models needed to match the real world characteristics of an MOV.  Comments & suggestions welcome.  VIDEO GENERATOR (NTSC)   An NTSC Video Generator useful for testing video detectors, DC restoration, etc.   Voltage-Controlled Capacitor (from external voltage source).  LTspice Symbol (ASY) included.

VoltageControlledInductor.pdf   Voltage-Controlled Inductor.  (Quicky example for S.E.D Usenet Group >:-}    Rudimentary Behavioral Model of Vishay VOM1271 PhotoVoltaic MOSFET Driver   Varicaps Modeled with a Lookup Table...No more nasty curve fitting!   Voltage Variable Resistor Subcircuit

A voltage variable resistor PSpice symbol (self-contained subcircuit)... Newly updated 03/18/2015: Now includes subcircuit representation and LTspice symbol (ASY).  Parameters are Vmax (full-scale control voltage) and Rmax (R value at control input equal to Vmax).   Caution:  Negative control voltage makes a negative resistor!   Need a zener in your simulation but have no Spice model?  Fudge it parametrically from the datasheet specifications.