Digital Potentiometer IC Distributor in China
- Provides Hookup accessories for Digital Potentiometer IC.
- Potentiometer IC have a singe high-speed voltage comparator.
- Compatible with most TTL and MOS circuit.
- It supports a dual-supply operation and single-supply operation.
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Professional Digital Potentiometer IC Supplier - Rantle East Electronic
Digital Potentiometer ICs are available at RANTLE from industry leading manufacturers. RANTLE Digital Potentiometer IC are incredibly useful, whether you’re controlling the volume on your stereo or the mood lighting in your room. The problem with traditional potentiometer is the fact that your microcontroller doesn’t have an easy way to interface with them.
Digital potentiometer can solve your problem by allowing you to control a voltage splitter with digital signals.
RANTLE provides Hookup accessories for Digital Potentiometer IC. The Accessories of Digital potentiometer IC allows for faster transfer rates and more memory. Digital potentiometer IC includes a plastic base plate, so you don’t have to worry about accidental electrical discharge.
If you are looking for LCD adjuster, op amp setting, or volume level, RANTLE Digital Potentiometer IC may suits what you need. This Digital Potentiometer IC has a small knob built right in and its breadboard friendly to boot!
RANTLE Digital Potentiometer IC have a singe high-speed voltage comparator. This device is designed to operate from a wide range of power-supply voltages. These are compatible with most TTL and MOS circuit.
RANTLE provides all kinds of Digital Potentiometer IC. Depending on your system, Digital Potentiometer IC can control your PC software. It supports a dual-supply operation and single-supply operation, making your device suitable for battery-powered applications and many other applications.
In addition, Digital potentiometer IC can operate in single-supply or dual-supply mode and incorporates an internal power supply from the USB.
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Digital Potentiometer IC: The Ultimate FAQ Guide
In this guide, you will find answers to all questions you may be having on digital potentiometers.
It covers everything – from definition, characteristics, design, working principle, quality testing to applications.
So, if you want to be an expert in the digital potentiometer IC industry, all information you need is here.
- What is Digital Potentiometer IC?
- What is Digital Potentiometer IC used for?
- How do you Choose Suitable digiPOT?
- What are the Advantages of Digital Potentiometer?
- Are there Limitations of digiPOT?
- How is the Resistive Digital-to-analog Converter Designed?
- How does Digital Potentiometer IC work?
- What are the Applications of Digital Potentiometer IC?
- How does Arduino Control Digital Potentiometer?
- How does Digital Potentiometer IC achieve Voltage Division?
- When do you Classify Digital Potentiometer as Linear Potentiometer?
- What are Logarithmic Potentiometers?
- Does a Digital Potentiometer IC Reduce Voltage?
- What are the Components of the Digital Potentiometer IC?
- Does Digital Potentiometer IC have Polarity?
- Why do Digital Potentiometers fail?
- How do you Classify digiPOT IC?
- What Parameters Affect Digital Potentiometer Performance?
- How does Digital Potentiometer compare to Analogue Potentiometer?
- Which Features are Unique to Digital Potentiometer IC?
- Why is MCP41010 Test Important?
- What are the Quality Standards for digiPOT IC?
- What is Rheostat?
- What is Unique in Digital Potentiometer IC Design?
- Which Type of Memory does digiPOT use?
- How do you Troubleshoot Digital Potentiometer IC?
- Why Replace Mechanical Potentiometer with Digital Potentiometer IC?
- Does Digital Potentiometer IC have Voltage Limit?
- Can Digital Potentiometer IC handle AC and Bipolar Operations?
- Do Digital Potentiometer ICs have Rated Current?
- What is a Dual Digital Potentiometer Chip?
- Can you connect Digital Potentiometer ICs in Parallel or Series?
- How do you Calculate Temperature Coefficient for Digital Potentiometer IC?
- Will Digital Potentiometer IC suffer from Leakage Currents?
- How does Resistor Differential Non-Linearity compare to Resistor Integral Non-Linearity?
- Will you Experience Cross Talk when using Digital Potentiometer IC?
- Can you Program Digital Potentiometer Chip?
- What is Total Harmonic Distortion in Digital Potentiometer IC?
- How can you Control Digital Potentiometer Chip?
- Do Digital Potentiometer Chips have EEPROM Memory?
- How can you Interface Digital Potentiometer Chip with other Components?
What is Digital Potentiometer IC?
This is an electronic component that is digitally and not mechanically controlled. It imitates the analog potentiometer functions.
It can be made on a resistor ladder IC or sometimes from the digital-to-analog converter. But the most preferred and common one is to have a construction of a resistor to the ladder.
The device can be used to adjust values through an external digital signal. This type of IC has no moving parts, and its environmental features have been improved.
Its automatic adjustment allows for a reduction in the adjustment processes.
This IC has control types that have features like up-down, 2-wire, SPI, and 3-wire interface, among others.
What is Digital Potentiometer IC used for?
This type of IC is used to fulfill two major functions. Through the microcontrollers, it is used for trimming and scaling analog signals.
How do you Choose Suitable digiPOT?
Selection of the right digiPOT calls for an understanding of the maximum voltage you need to apply to the terminals.
This is because the power supply will help in defining the voltage signal boundary conditions.
The following are some of the factors that can guide you in selecting the best digiPOT.
· Resistor Configuration
You can configure a digiPOT into two modes, potentiometer or rheostat. A potentiometer mode has three terminals:
Basically, the digiPOT divides voltage.
The voltage between A and B is proportional to the wiper voltage. It is also proportional to the resistors RAW and RWB.
The applications for potentiometer mode include DAC, LCD VCOM adjustment, and analog signal attenuation.
Rheostat Mode, on the other hand, uses only two terminals.
The terminal that is not being used can either be tied to the terminal W or left floating.
The wiper terminal can access two contact nominal end-to-end resistance points of the digiPOT.
The least wiper resistance is situated at the first B terminal connection. This represents a zero scale.
Rheostat mode is used in making wheat stone bridge calibrations and Op-amp gain control.
· Digital Interface
ADI is a larger digital potentiometer portfolio that can support many varying digital interface.
For instance, ADI offers an SPI compatibility interface that runs at a speed of 50 MHz clock rate. It’s also ideal for a standard fast mode of 400 MHz clock rate.
When two push-buttons are added, you can easily interact with the device. The resistance can be increased by pressing the up button and reduce it by pushing the down button.
This makes it easy to operate the device.
· Internal Memory
There are four different integrated memory that is supported by various ADI’s portfolios. This allows the user to choose the correct digital potentiometer for their applications.
The user can set the wiper’s power-on reset to a programmed value through the help of the internal memory.
Even when the wiper position is reprogrammed, it will still go back to the initial programmed position on the power-up.
Normally, it is critical for situations that require fast power on time.
· Supply Voltage
This is also a factor that influences the selection of a digital potentiometer.
You should know the maximum voltage (electrical signal) to apply on the terminals of the potentiometer.
· End-to-end resistance
ADI also provides many end-to-end options for resistors.
With this information, you can easily achieve better:
- Bandwidth and noise performance
- Power dissipation
The resolutions being offered by ADI range from 5-bit to 10-bit. This results in LSB sizes that are as low as 4 Ω.
The need for more resolutions will mean calling for the implementation of a cascade, serial, or parallel digiPOT combinations.
· Key Performance Parameters
These include the resistor tolerance error, which is also the absolute end-to-end. It is ±20% and can be an important factor if it is matched to an external discrete resistor.
· Packages of digiPOT
This is also an influencing factor. A digiPOTS have different packages that you can choose from. These include: SC70, LFCSP, SOT-23, MSOP, TSSOP and SOIC.
What are the Advantages of Digital Potentiometer?
Digital potentiometer circuit
A digital potentiometer has many benefits. These include the following.
- It is adjustable and can be used to adjust the currents by varying the resistance of a machine. Therefore, it can be used to solve the user-adjustable resistance requirements.
- It can offer a wide array of end-to-end resistors.
- Because it has no mechanical elements, it is resilient to shock, wear, aging, and contact. It is also resistant to dust, moisture, or any environmental conditions.
- It can use only two terminals instead of three, and this results in a rheostat.
- Many functionalities can be provided in a very small footprint when you use a digital potentiometer.
- It can also provide a wide range of resolutions.
Are there Limitations of digiPOT?
Yes, there are some shortcomings associated with digiPOT. For example,
- A digital potentiometer cannot withstand large voltages.
- It cannot carry a large current.
- In addition to these, it cannot dissipate large power.
- They are restricted by a current limit in the range of 10s of milliamperes.
- The digiPOT constrain its voltage range to the two input terminals of the digital supply range of between 0-5 VDC.
- It requires special logic to check the zero crossings of an analog. This helps in allowing the resistive values without generating an audible click on the output on audio amplifiers.
- Their resistance defaults to a different value when there is a power cycle. It’s only valid when there is a correct DC supply voltage. Removing the voltage disconnects the resistance between the two ends rendering the wiper undefined.
How is the Resistive Digital-to-analog Converter Designed?
A DAC is a circuit converting the digital-to-analog signal. It has different step sizes that help in designing it.
To design this, you have to know that it uses only two resistance values R and 2R. This is not influenced by the number of bits of the converter.
The state of B2, B1, and B0 determines the respective switching on I2, I1 and I0 currents to the ground.
The analysis is done by observing the connectivity of the output to V-through R. This is the op-amp in a negative feedback configuration.
How does Digital Potentiometer IC work?
It works through the use of digital signals and switches. In the middle of the potentiometer, there is a resistor ladder that has electronic switches located at its every step.
Switches are closed one at a time. This helps in determining the wiper position and resistance ratio. The number of steps in the ladder is used to determine the resolutions of the digiPOT.
What are the Applications of Digital Potentiometer IC?
The applications of digital potentiometer are many. Below are some of them.
- They are used in the manufacturing of communication equipment like cell phones, exchangers, facsimiles, and other wireless devices.
- Digital potentiometer IC is useful in sensor trimming and calibration, whether remote or local.
- They are used in the manufacturing of broadcasting equipment such as professionals use camcorders, color monitors, and VTR equipment.
- DigiPOT can also be used to adjust gain amplifiers.
- In addition to these, they are used in audio level control.
- Digital potentiometers are also found in power supply equipment like switching power supplies, battery chargers, and assorted power supply circuit.
- Sensor devices also use the technology of digital potentiometer IC. For instance, photoelectric, pressure, encoder, and magnetic sensors also use digital potentiometer ICs.
- They are also used to match line impedances.
- Computer and peripherals are also made with digital potentiometer ICs. The examples, in this case, include a laser beam printer, displays, notebook computer, and projectors.
- Apart from these, the optical network also has a digital potentiometer IC.
- Automotive electronics are also not left out. The digital potentiometer ICs are also used to adjust their level.
- Other machines made with digital potentiometer include hematology analyzers, TV, robots, and programmable controllers.
- Lastly, it is used in programmable power supply, filters, time constants, and delay values.
How does Arduino Control Digital Potentiometer?
The digiPOT is normally used when you intend to vary the resistance in a circuit electronically.
It can be used to adjust the circuit resistance, and this will allow you to control the voltage splitters. This is done through digital signals.
Arduino aids in controlling the digiPOT in the following four steps.
- First, prepare the materials like the Arduino board, Digital potentiometer MCP41100, and a resistor 100 ohm. In addition to these, you will also need LED, bread-board, and jumpers.
- Secondly, you have to calculate the resistance. This is done by connecting the pins 3, 6, and 7 of the AD517 to the ground. After this, connect pins 2 and 8 to the +5V.
The next step is to connect the pin 4.
That is to connect the digiPOT’s clock pin to the analog pin 5 of the Arduino. The pin 5 which is the data line, is also connected to the analog pin 4.
You can now add 4.7k ohm pull up resistors to both the digital port’s clock pin and the data line.
This is done to make a connection between both lines to the +5V.
Wire an LED to pin 1 and connect the AD5171’s wiper with a 680 ohm LED in series.
- The third step is to generate the Arduino code, which is used to control the digital potentiometer.
- The fourth is to use it in simple applications like a motor drive or an LED controller.
For instance, let’s control the brightness of six LEDs using a six-channel digiPOT.
Arduino, digiPOT, 6LEDs, 6 220 ohm resistors, hookup wires, and bread-board are the hardware required.
DigiPOT has six variable resistors which are built-in for separate electronic controls.
Arduino digital potentiometer
How does Digital Potentiometer IC achieve Voltage Division?
It does achieve voltage division through the three-wire resistances that acts as the voltage dividers. The three wires produce a continuous variable voltage output signal.
These are proportional to the physical position of the wiper located along the track.
When do you Classify Digital Potentiometer as Linear Potentiometer?
The digital potentiometer is normally classified as linear when the resistive strip is aligned in a straight track. It has a resistive element of constant cross-section.
This cross-section leads to a resistance between the wiper and the end of the terminal.
This type of potentiometers produces different resistance outputs based on the shifting of a slider or wiper.
Linear potentiometers have three leads of variable resistors. Two of the three leads are connected to the ends of the resistor. This helps to make the resistance between them fixed.
What are Logarithmic Potentiometers?
These are potentiometers that can be used to control the audio devices’ volumes. This is relevant because the human ear responds to the sound loudness is also logarithmic.
It provides an opportunity to magnify the volume.
This type of potentiometers is built with a bias into its resistive element.
That is, the potentiometer center position is not even half the total potentiometer value.
It’s called logarithmic because the resistive elements are designed to follow a logarithmic taper or a mathematical square profile.
The logarithmic potentiometer is made from materials that have different resistivity from one end to the other.
This characteristic produces devices with an output voltage that has a logarithmic function of the wiper position.
Some logarithmic potentiometers are very cost-effective.
These are not logarithmically accurate. Instead, they use two regions of different resistance, though constantly resistive, to approximate a logarithmic law.
As the potentiometer rotates, the two resistive tracks overlap at 50%, leading to a stepwise logarithmic taper.
A true logarithmic potentiometer is relatively costly. They are useful in controlling volumes and signals level in an audio system.
This is because human beings perceive audio volume as logarithmic.
Does a Digital Potentiometer IC Reduce Voltage?
Yes, it does.
This is done by adjusting the output voltage at the error amplifier pin.
The adjustments are made within narrow limits so that tolerances can be removed. It also helps to facilitate the dropping of the power path.
The reduction of voltage by a digital potentiometer is normally a useful function carried out in a circuit test.
It is done to verify if the device can work effectively at a nominal power supply of ±10%. This procedure helps in changing the voltage supply to an expected range.
Output changing applications like the dynamic voltage on fly facilitate the reduction of voltage in low power modes.
What are the Components of the Digital Potentiometer IC?
There are several components of a digital potentiometer. It is these components that help the device to function optimally.
These parts include resistor array, wiper switches, and a control section.
Others include memory IC for information recovery, the control section, and the INC, which is the signal controlling wiper movement.
In addition to this, there is a chip selection (CS). This can be enabled so that it can be used as an address input for multiple digital pot applications.
Lastly, a digital potentiometer has a U/D, which is the up and down signal. This can be enabled to set the pot’s wiper direction.
Digital potentiometer circuit
Does Digital Potentiometer IC have Polarity?
Yes, it has.
It has a three-terminal device that has an internal architecture composed of an array resistor and switches.
Between the terminals A and B, there exist series of resistors which are passive.
The wiper terminal (W) is programmed digitally to reach the 2n tap points located on the resistor strings.
The resistance between A and B terminals is normally called end-to-end resistor, which spans from 1KΩ to 1MΩ.
The resistance between terminal A and W (RAW) and that between terminal B and W (RBW) are complementary.
This means that the increase of RAW results in the same proportion decrease in RBW.
No voltage polarity restriction is being applied to terminals A, B, and W.
The voltage across the terminals A to B, W to A, and W to B should be at either polarity.
Also, the most important thing here is to make sure the signal is not more than the power supply rail.
In addition to these, the current can flow in any direction without any limits. This can also happen successfully when the current does not go beyond the density specification.
Why do Digital Potentiometers fail?
This can occur when the prescribed power-up sequence is not adhered to by the user resulting in a short circuit.
A short circuit can also be experienced when there is a dual- supply of power. In this case, a greater voltage is applied across terminals A-B, W-B, and W-A.
This can also lead to the failure of a digital potentiometer.
How do you Classify digiPOT IC?
It can be classified into two types. There is a digital version that is of a mechanical potentiometer and another one called a rheostat.
i. Mechanical Digital Potentiometer
The mechanical digiPOT does not allow rotation beyond endpoints. It has a single-turn potentiometer with a casing metal that can be removed to expose wiper contacts and resistive tracks.
This type of potentiometer completely controls the gadget range of operation since it’s a voltage divider.
When a mechanical potentiometer wiper is connected to the terminals, it’s transformed to rheostats of variable resistors.
Its resistor is fixed in a circular track form, and it can stop a short of a full circle. This occurs at 270 degrees.
The track is engrained in a ceramic base and its two ends of resistance form terminals.
These terminals can be soldered on to a PCB or make a good wire termination.
Additionally, the resistance in a mechanical potentiometer may vary from a few ohms to many hundreds of ohms. The whole device is enclosed in a package where the wiper is included.
ii. Rheostat Digital Potentiometer
This is also a variable resistor that is used to control the current. It can be in applications that need electric current adjustments.
For instance, you can adjust current flow in generators, dim lights, and motor start or control speed through a rheostat.
What Parameters Affect Digital Potentiometer Performance?
Many features affect the performance of the digital potentiometer. For example,
- A linear, integral, and differential voltage input signal are some of the determinants of its performance.
- Maximum current and power that should be power-up can also are some determinants for its performance.
- It should also have an end-to-end resistance and its accuracy, which is known as RpoT. This will also influence its performance.
- Apart from these, the good performance of a digiPOT requires a wiper resistance and current of RWi and IW.
- An interface of tolerance and temperature coefficients of TCRpoT and TCRATIo also makes it perform well.
- In addition to these, a digital potentiometer performance is also influenced by the channel density.
- Pot pins that limit the voltage are also known to influence how a digital potentiometer works.
- Lastly, a good digiPOT performance is characterized by the presence of an isolation resistance of RISo.
How does Digital Potentiometer compare to Analogue Potentiometer?
Both of these potentiometers have some similarities that make them easy to use interchangeably in some applications.
For example, they can provide a wide array of end-to-end resistances.
Other than these, they can also be used in solving the need for a user-adjustable resistance.
In addition to these, they both set an analog output through the use of digital input signals.
However, some differences exist between these two potentiometers. For instance, a digital potentiometer can allow an adjustment of an analog voltage.
On the contrary, the analog one adjusts the current and voltage.
The analog potentiometer can withstand large voltage, whereas the digital one cannot.
The analog potentiometer has the capability of carrying large currents and can also dissipate large power. This is not the case with the digital potentiometer.
The design of the analog potentiometer makes it susceptible to changes in performance and reliability over time.
On the other hand, the design of the digital potentiometer guarantees consistency and reliability in performance.
The analog potentiometers are very sensitive to shock and vibrations while the digital one is resistant to shock and vibration.
The digital potentiometer resists wearing, aging, and contact, whereas the analog one is not.
Therefore the lifetime of an analog potentiometer is shorter in comparison to that of a digital one.
Which Features are Unique to Digital Potentiometer IC?
Digital potentiometer IC has some unique features. These features are not in analog potentiometer, and they include the following:
- A digital potentiometer has one package of a quack-pack.
- It has a shut-down mode for closing a device.
- The IC also has a pre-set position that has been programmed upon the power-on for the wiper.
Why is MCP41010 Test Important?
MCP41010 test is important because it works faster than when a potentiometer is turned on by hand.
It also facilitates a quick reading of off a voltmeter. Apart from these, the test generates more accurate data about a digital potentiometer.
What are the Quality Standards for digiPOT IC?
The quality standards for digiPOT IC are many. These include the following:
· It should have Temperature Compensation
A good digital potentiometer should have an internal EEPROM that will help in storing thermal calibration when the temperature increases.
Inside the compensation, there are temperature sensors that aid in measuring the ambient temperature.
The digital potentiometer can adjust the temperature through the modifiers located in the lookup table.
· It has to be Nonvolatile
The digital potentiometer should be a commonly used one, which is cost-effective. It should be able to retrieve information even when it’s powered down.
The EEPROM technology inbuilt in digital potentiometer guarantees 50,000 writes cycles without any loss of information.
This qualifies it to be a reliable digital potentiometer IC.
The one-time programmable digiPOT, for instance, the MAX5427 to MAX5429 can permanently keep their default wiper positions through fuse programming.
· It should have a Factory Calibration
The voltage and current should be automatically calibrated for power and other systems right from the factory.
This will helps you to increase your device manufacturing output, improve accuracy and reliability.
· The Push-button Interface
A good digital potentiometer must have this. This button helps to advance the wiper at different rates depending on the time taken to press it.
The push-button does not need a microcontroller, and for this reason, it makes the system simpler.
Besides, the de-bounced push buttons interface is specifically used in adjusting audio volumes.
· It should have a Zero-crossing Detection
Digital potentiometers used in audio applications should have this feature.
This is because it helps in reducing the audible clicks and pops that may occur when wiper transitions between settings.
If the zero crossing is active, it delays wiper transitions until VL becomes equivalent to VH.
They often show maximum wiper transitions delay, and this helps to facilitate specialized circuits.
What is Rheostat?
Rheostat has been derived from the Greek word “rheos” and “statist.” This means a device that is used to control a stream. In this case, it is a variable resistor that is used to control the current flow.
It’s normally a wire wound around a ceramic core, and a wiper is placed on top of the windings.
In a rheostat, the flow of an electric current is influenced by voltage quantity and the total electrical circuit resistance.
Reducing the circuit resistance prompts the increase in the electric current flow through the circuit.
On the contrary, an increase of the circuit resistance promotes the decrease in electric current flow through the circuit.
When an electric current has a rheostat, it’s easy to control the electric current flow in a circuit. It can reduce the flow of an electric current to a certain level but not block it completely.
What is Unique in Digital Potentiometer IC Design?
The unique thing about digiPOT IC design is that it has been designed with flexible systems that are multi-functional.
For instance, it’s used as a feedback resistor in an op-amp.
This allows the gain of the op-amp in an alternative way, which varies according to the amplitude of components.
Therefore, components are reduced, and the input signal is maximized, and this results in a small PCB footprint.
Which Type of Memory does digiPOT use?
DigiPOT normally uses volatile memory, which they don’t show when they are powered down.
When powered up, it reports a default value, which in most cases happens to be the midpoint value.
A microcontroller helps in restoring the previous position, which is interfaced.
In addition to this, a digital potentiometer can sometimes store information in non-volatile memory.
In this case, the values read when it’s on power-up are the same as when it’s powered down.
How do you Troubleshoot Digital Potentiometer IC?
Just like other devices, a digital potentiometer IC also has some issues. These problems may compromise its functionality and may not yield the expected results.
For example, there could be an issue of the too-high circuit of 16Ma in LM2577. This is a problem that could be resolved by using current limiting resistors.
Secondly, the digital potentiometer IC also may develop an issue of too high variable resistor voltage in the LM2577.
Why Replace Mechanical Potentiometer with Digital Potentiometer IC?
The mechanical potentiometer can be replaced with a digital potentiometer for several reasons. For example, a digital potentiometer is reliable and uses less space since its PCB footprint is smaller.
Therefore, it is more convenient to use it than a mechanical one.
You can choose a digital potentiometer because it also performs better and is less prone to noise than the mechanical one.
In addition to these, a digital potentiometer is resilient to shock, vibration, wear, aging, and contact.
Because of this characteristic, you can choose to use it instead of the mechanical one since it can last longer.
The digiPOT is also less sensitive to dirt, dust, and moisture.
These environmental conditions can easily degrade a mechanical potentiometer because it is sensitive to such.
Does Digital Potentiometer IC have Voltage Limit?
Yes, it has.
The digital potentiometer usually limits their voltage to only two terminal resistors, which may range between 0-5VDC.
When a multiplying DAC is used as a digital potentiometer, it works well with a voltage of up to 15V. This will have 16-bit control.
The most essential factor is that there must be a good voltage supply that is furnished.
Can Digital Potentiometer IC handle AC and Bipolar Operations?
Yes, some of the digital potentiometers can specifically handle operations from both of them. These are rated for ±15 V with an operating current that could be as low as 0.01 µA.
Do Digital Potentiometer ICs have Rated Current?
Yes, they do. Most of them are normally rated at 5 Vdc and 10KΩ. In addition to these, sometimes others can be rated at a value of 5, 50, and 100 KΩ.
The standard tolerance was once 20%, but currently, things have changed. Today, there are digital potentiometers that can tolerate up to as low as 1%.
What is a Dual Digital Potentiometer Chip?
Dual potentiometer chip
This is a chip that is composed of two solid-state potentiometers that are digitally controlled. Each of the potentiometers has 256 resistive sections and can be connected in a stack.
These two state potentiometers help in increasing the total resistance with the same resolution.
The tap points that are accessible to the wiper are located at the end of the potentiometer. They are also found between the resistive sections.
The wiper position on the resistive array is set by the value of an 8-bit. This helps to control the connection to the wiper output.
Both the control and communication through the device are done through a 3-wire serial port interface. This promotes the reading or writing of the wiper position.
A dual digital potentiometer is available in three different standard resistances, namely, 10, 50, and 100 k ohm versions.
Apart from these, it is also available in 14-pin, 16-pin, and 20-pin packages.
Upon powering the device, the two 8-bit values contained in each potentiometer are written on a 17-bit I/O shift register. This is because the two wiper positions are stored in the registers.
The 3-wire serial port interface helps in driving the internal control unit. This aids in completing the communication and the control of a dual digital potentiometer.
This 3-wire serial interface is composed of RST, CLK, and DQ input signals.
The RST control signal helps the 3-wire serial port in the device to function properly. When the RST is high, it facilitates the selection of the chip.
Any communication in a dual digital potentiometer can only begin when the RST is high.
The CLK is useful in generating timing synchronization for both data input and output.
The DQ, on the other hand, transmits wiper settings of the dual digital potentiometer to the 17-bit I/O shift register.
The selected settings and stack bit configurations are also moved to the same register.
Dual digital potentiometer possesses the following features:
- It consumes relatively low power.
- The serial ports avail the means for setting and reading both potentiometers.
- Its resistors can be connected to have improved total resistance.
- A dual digital potentiometer can operate under an industrial temperature range of 40°C +85°C
Can you connect Digital Potentiometer ICs in Parallel or Series?
Yes, it is possible. These are the first ways in which a 3-wire bus can be connected to enable communication with multiple chips.
These connections prompt data writings to the parts in a 17-bit block one after the other.
Connecting a digital potentiometer in a series interface encourages sequential data sending off one bit after the other. This takes place on one input or output line.
The digital potentiometer parallel connection sends all the data simultaneously, and this calls for a separate pin for every bit.
The parallel connection is ideal for applications that consider speed as an important aspect.
On the other hand, a series of digital potentiometer connection is preferred when you want a cost-effective connection that is smaller.
How do you Calculate Temperature Coefficient for Digital Potentiometer IC?
Calculating the digital potentiometer temperature coefficient calls for tying the H and L terminal to the Vcc and ground, respectively.
You can then use a two-wire interface, and this results in the changing of the position of the potentiometer.
Thereafter, measure the voltage on the W terminal for every position of the potentiometer over the temperature.
The temperature coefficient changes with different device configurations. The end-to-end temperature coefficient is 750ppm/°C, according to the datasheet state.
The temperature coefficient is very lower when the digiPOT is in voltage divider mode. This is because of every resistor branch temperature coefficient council each other.
The wiper resistance will now be prompted to affect the temperature coefficient.
Will Digital Potentiometer IC suffer from Leakage Currents?
No, it will not. This is because it utilizes a standard static CMOS logic that dissipates power while it updates.
After updating, only a very small decimal fraction of leakage current flows.
This is reduced to zero current leakage immediately; a digital shutdown mode opens the variable resistor in a circuit.
Because of this, there is no way a digital potentiometer IC will suffer from leakage currents.
How does Resistor Differential Non-Linearity compare to Resistor Integral Non-Linearity?
Resistor differential non-linearity is the deviation between two values of analog that are adjacent to the input digital values.
This can be used to test for errors in the digital-to-analog converter only. It helps to determine the accuracy of a digital-to-analog converter.
When a differential non-linearity is greater than 1 LSB, there could be a non-monotonic transfer function in DAC.
The differential resistor non-linearity indicates a bad case of deviation from the ideal 1LSB step.
For instance, a 1.5 LSB output change for a 1LSB digital code change has a half LSB differential non-linearity.
Resistor differential non-linearity is normally expressed as a fraction or sometimes as a full scale. When it is less than 1 LSB, it may create missing code.
On the other hand, integral non-linearity is used to measure the performance in Digital-to-Analog Converters and also in analog-to-digital converters.
It’s used in DAC to measure the recommended deviation between the output and the actual measured output value.
This measurement is for a particular input code.
ADCs measure the deviation between the ideal input threshold value and that of the given output code. The integral non-linearity is always performed once you have compensated for an offset and gain error.
It is dependent on the line that has been chosen. This could be the line connecting the end-point of the transfer functions.
Apart from this, the best fit line can be used to minimize the average integral.
Resistor integral linearity is used to describe the shape of an A/D’s transfer features.
The deviation that is measured through the integral linearity causes inaccuracy that may be more than the recommended amount.
This causes what we call integral linearity error.
This measurement of offset and gain error is calibrated to zero because they can be canceled out in actual use.
Will you Experience Cross Talk when using Digital Potentiometer IC?
Undesired coupling between signal paths is what is referred to as cross-talk.
It’s also a disturbance from the electric field of a telecommunication signal that affects other signals in the adjacent circuit. Cross-talk can be caused by three things:
- Electric coupling between transmission media like wire pair on VF cable system. Alternatively, it could be caused by an imbalance in the capacitance between wire pairs in a cable.
- Bad filters that may have been designed poorly may result in poor frequency response control.
- A non-linear performance in the analog multiplexer system may also cause cross-talk.
Cross-talk can either be intelligible or unintelligible.
In intelligible cross-talk, four words can be comprehended by the listener from a conversation in seven seconds.
Un-intelligible cross-talk comes from other forms of disturbing effects; for instance, it may come from one channel to another.
The intelligible cross-talk causes a lot more problems than its counterpart. This is because the listener may fear of losing privacy in a conversation.
Cross-talk takes place in microcircuits that are within the audio machines and also within a circuit network.
Digital potentiometer settings are stored in EEPROM, where they can be retained even when the power is cycled.
The design of a digital potentiometer is programmed in such a way that it helps to minimize cross-talk.
This is done when, for example, dual digiPOT provides 0.5Db channel-to-channel matching that helps in avoiding volume differences between channels.
In some cases, cross-talk may be evident in digital potentiometer ICs, but this may be very negligible.
Can you Program Digital Potentiometer Chip?
Yes, it can be programmed in a very simple way. This can be done through a digitally programmable potentiometer generated from a catalyst semi-conductor. It provides one-time wiper programmability through a simple two-wire interface.
When you want to program it, you can set the wiper value after power on. To avoid future adjustments, you can disable the interface.
What is Total Harmonic Distortion in Digital Potentiometer IC?
This is a measurement of harmonic distortion in a signal. It is the ratio of all harmonic components added together to the power of fundamental frequency.
Total harmonic distortion in digital potentiometer IC is used to count the non-linearity of a machine as an attenuator.
The presence of non-linearity is because of the internal switches and their RON variation with the voltage.
The golden rule is that when the nominal digital potentiometer resistance is higher, the total harmonic distortion becomes better. This is because the denominator is larger.
In a digital potentiometer, the total harmonic distortion is a very critical factor to consider when sourcing for a digiPOT device.
How can you Control Digital Potentiometer Chip?
This is controlled by a digital signal. In the middle of the potentiometer, there is a resistor ladder that has many switches at its every step.
To control the digital potentiometer, close the switches one after the other. This will help you to determine the wiper position and the resistance ratio.
The resolution of a digital potentiometer is dictated by the number of steps in a ladder. As you close the switches one after the other, you will be able to control the potentiometer chip.
Do Digital Potentiometer Chips have EEPROM Memory?
Yes, some of them have.
This is because they are integrated circuits with some variants that possess nonvolatile memory.
The EEPROM helps the digiPOT to remember the wiper position. It helps to maintain the digital potentiometer settings even when the power supply is off.
For instance, when the on-board memory is missing, the original wiper position is usually the middle value.
How can you Interface Digital Potentiometer Chip with other Components?
This can be done through a series of steps of connections. For example, you can pair it with an Arduino in the following steps.
- First, you have to wire 5v to VDD (8) and PA (5)
- Secondly, connect the ground to PB (7) and VSS (4).
- Thirdly, connect a resistor found in the 100 range to PW (6), and thereafter connect it to an LED.
- Next, connect the LED to the ground so that the circuit can be connected.
- The fifth step is to connect Arduino pin 10 to CS (1) on the mcp41XXX.
- After this, connect pin 11 to SI (3).
- Lastly, pin 13 is connected to SCK (2).
After making all these connections, LED-Blink sketch that has an SPI communication library is loaded on to the Arduino.
The complete interface can then be used to improve the parameters of the programs to see whether it changes operation.
As you can see, there are many parameters to consider before choosing digital potentiometer IC.
And, this guide, has for sure made everything simple for you.
However, if you have questions on digital potentiometer chip, you can talk to experts now.