The i2c serial interface is a very popular one, but digital potentiometers are also available with the spi, updown counter, and manual incrementdecrement interfaces. We know the analog potentiometer, is a threeterminal resistor with a sliding contact that forms an adjustable voltage divider. Mode of operation overview ltspice iv has two basic modes of driving the simulator. The linked sites, articles and presented information are provided as a useful insight to help you decide on the type of engineering expert you might need. Its internal resistance is affected due to variation in temperature. Floating either terminal a or b allows the devi ce to be used as a rheostat variable resistor. The function of the potentiometer section of the digital potentiometer is the same as the mechanical version. Choosing the correct digipot for your application analog devices. The video helps you in adding a custom digital logic components in ltspice to simulate basic digital combinational and sequential circuits. Thanks for contributing an answer to electrical engineering stack exchange. I have gone to the yahoo groups lt spice and downloaded some potentiometers symbols and. Figure 2 shows three examples of digital potentiometers that are all offered in small packages. Singledual digital potentiometer with spi interface.
Digitally controlled potentiometer xdcp datasheet the x9c102, x9c103, x9c104, x9c503 are digitally controlled xdcp potentiometers. Advantages of digital potentiometer,disadvantages of. Since a simulation can generate many megabytes of data in a few minutes, free. Modeling potentiometers and variable resistors pspice. Computer modeling of electronic circuits with ltspice. Ltspice tutorial introduction while ltspice is a windows program, it runs on linux under wine as well. Electrically, a potentiometer consists of two resistors connected in series. The potentiometer is a three legged animal having a fixed resistance between its outer legs. The digital potentiometer is a mixed signal device designed as an electronic replacement for mechanical potentiometers. In this tutorial you will learn how to control the ad5206 digital potentiometer using serial peripheral interface spi. Figure 5 potentiometer circuit finally, we will let the potentiometer wiper be a variable parameter instead of a fixed value. A digipot is a digitally controlled device that can be used to adjust voltage or current and offers. The wiper position varies linearly and is controlled via the spi interface.
Choosing the correct digipot for your application solutions bulletin pdf. In this application note, we will model potentiometers and variable resistors using orcad capture and simulate the example circuits, which include models of potientiometer and variable resistors, using pspice. Intermediate ltspice tutorial august 04, 2015 by trevor gamblin ltspice possesses several features that can be used to test your design beyond simple transient analysis and ac sweeps. Ltspice tutorial the complete course simon bramble. Compare and select from tis portfolio of digital potentiometers to meet the needs of your system design. I was looking on the forum about potentiometers, but nothing was done. Ad5233 nonvolatile memory, quad 64position digital. The mcp4142xx family is available with endtoend resistor values of 5k. Im told that someone has posted presumably on the yahoo. The device consists of a resistor array, wiper switches, a control section, and nonvolatile memory.
I have a folder named new in both the sub and sym folders. A digital potentiometer or a digipot electronic potentiometer as it is commonly called can be said to be a digital version of the mechanical potentiometer or a rheostat. The middle leg functions like a wiper you can slide along its length. This article will go over a few advanced functions. In addition, we offer inductor equivalent circuits. Spicesimulation using ltspice iv reverse engineering. Digital potentiometers design guide microchip technology. Few digital pots can source or sink more than 20 ma at output and 1ma is usual. Know about digital potentiometer pot abstract the digital pot is a mixed signal device. Analogto digital converters adcs 932 highspeed adcs 10msps 346 isolated adcs 33. Changes to manual control with rotary encoder section 11. I think that you were doing some basic how to videos with ltspice awhile ago.
Ltspice is node unlimited, incredibly easy to learn and can be used to simulate most of the analogue components from linear technology as well as discrete and passive components. The specification for the potentiometer consists of. The gsdadp allows the user to adjust the displayed value via the frontpanel push buttons. The wiper essentially splits the fixed resistor r1 in two resistors, r1a and r1b. The archers paradox in slow motion smarter every day 6 duration. Is there a database on internet for ltspice models. For an explanation of spi see the spi library reference digital potentiometers are useful when you need to vary the resistance in a circuit electronically rather than by hand. The mcp41100 has outstanding ac and dc characteristics, and consumes digital potentiometers with an spi compatible interface. As discussed previously, digital potentiometers allow you to control resistance using digital inputs. What is the resistance tolerance of the digital potentiometers. Single channel, 1024position, 1% rtol, digital potentiometer with 20times.
It was foreseen to simulate switching power supplies using the semiconductors of the enterprisebut can also be used for nearly other electronic purpose. And8414 everything you wanted to know about digital. Microchip offers digital potentiometer devices with typical endtoend resistances of 2. As the wiper slides toward the cw end, r1a gets bigger as r1b gets smaller. Ironhorse gsdadp digital potentiometer general information the gsdadp digital potentiometer is a compact, microprocessorbased unit capable of being either field or factory configured for a number of industrial userinterface control signal needs. This is an instruction to step the parameter r from 0.
We offer spice, ltspice, sparameter and 3d files on many of our parts. It offers the same analogue functions as a rheostat or a potentiometer that is control of current or voltage. In the scratchpad programming mode, a specific setting can be programmed directly to the. Analog devices offers a wide range of digital potentiometer digipot. Analog devices portfolio of digital potentiometers provide uncompromising. The libraries and components models of ltspice free. The digital portion contains the interface, control, and registers associated with the potentiometer. The threeterminal digital potentiometer shown in figure 1a above is essentially an adjustable resistive divider with a fixed endtoend resistance. The ad5293 is a singlechannel, 1024position digital potentiometerin this data.
The wiper position is controlled by a threewire interface. Using an analog voltage to control a digital potentiometer. Ltspice is also called switchercad by its manufacturer, since they use it primarily for the design of switch mode power supplies smps. Following are the drawbacks or disadvantages of digital potentiometer. Ltspice getting started guide university of colorado boulder. But avoid asking for help, clarification, or responding to other answers. The analog portion of the device is the threeterminal analog component called potentiometer. The low resistor tolerance and low nominal temperature coefficientsimplify openloop applications as well as applic. Ti home data converters digital potentiometers digipots data converters. The wiper position of the mcp41xxx42xxx varies linearly and is controlled via. The mcp41100 is a singlechannel, 8bit digital potentiometer features 100k. It presents a method of creating a tolerably accurate spice model of the humble potentiometer.
There is a spice model netlist containing the analog portion. Use the program as a generalpurpose schematic capture program with an integrated simulator. The mcp41xxx is a singlechannel device and is offered in an 8pin pdip or soic package. But these are potentiometer files someone have made, that you have to import into ltspice. Digital potentiometer a digital potentiometer often called digipot is an electronic component that mimics the functions of analog potentiometers. The rl is a ratio of the rpot 10k divided by your b list. Ltspice contains models for most ltc power devices and many more. The potentiometer is implemented by a resistor array. In both cases, the potentiometer or pot is a three terminal device. Pdf modelling potentiometers in spice researchgate. Using arduinos i2c wire library, the digital pot will step through 64 levels of resistance, fading an led the i2c protocol involves using two lines to send and receive data. This example shows how to control a analog devices ad5171 digital potentiometer which communicates via the i2c synchronous serial protocol. It can be downloaded from the web without any problems or fees but the usage is a little tricky a mixture of command. Through digital input signals, the resistance between two terminals can be adjusted, just as in an analog potentiometer.
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