Main Content

The MCP41HVX1 family of digital potentiometers (aka DigiPots) are devices that mimic the function of an analog potentiometer and are controlled thru SPI. An example application would be replacing the volume knob on your stereo with a DigiPot that is controlled by an Arduino. This assumes that the volume control on your stereo is a potentiometer and not a rotary encoder.

MCP41HVX1 are a little different then other DigiPots in that they have a split rail design. This means that while the DigiPot itself can be controlled by the output voltage of an Arduino, the signal that is passed thru the resistor network works with a far greater range of voltage (up to 36 volts). Most DigiPots that can be controlled by 5 volts are limited to 5 volts across the resistor network which restricts their usage for retrofitting an existing circuit that operates on higher voltage such as what you would find in a car or boat.

The MCP41HVX1 family is made up of the following chips:

MCP41HV31-104E/ST - 100k ohm (7 bits)
MCP41HV31-503E/ST - 50k ohm (7 bits)
MCP41HV31-103E/ST - 10k ohm (7 bits)
MCP41HV31-502E/ST - 5k ohm (7 bits)
MCP41HV31-103E/MQ - 10k ohm (7 bits)
MCP41HV51-104E/ST - 100k ohm (8 bits)
MCP41HV51-503E/ST - 50k ohm (8 bits)
MCP41HV51T-503E/ST - 50k ohm (8 bits)
MCP41HV51-103E/ST - 10k ohm (8 bits)
MCP41HV51-502E/ST - 5k ohm (8 bits)
The 7 bit chips allow for 128 steps in the resistor network and 8 bit chips allow for 256 steps in the resistor network. This means that 8 bit chips allow for twice as many resistance values from the potentiometer.

Choose the appropriate MCP41HVX1 chip from the list above. The chip you select is based on the resistance range required for your application. This Instructable is based on the TSSOP 14 package versions of the chip so to follow along with this guide pick any chip in the list except for the MCP41HV31-103E/MQ which is a QFN package. It is recommended to get a few extra chips as I did encounter a bad one and they are inexpensive. I ordered mine from Digi-Key.
Secondary DC power supply that is from 10 to 36 volts. In my example I use a 17 volt wall wart DC power supply from my box of old power supplies.
Soldering flux
Soldering iron
Tweezers and\or toothpick
TSSOP 14 pin breakout board - Amazon - QLOUNI 40pcs PCB Proto Boards SMD to DIP Adapter Plate Converter TQFP (32 44 48 64 84 100) SOP SSOP TSSOP 8 10 14 16 20 23 24 28 (Assortment of sizes. Plenty available for multiple projects)
Quantify of 2 - 7 pin headers - Amazon - DEPEPE 30 Pcs 40 Pin 2.54mm Male and Female Pin Headers for Arduino Prototype Shield - (Cut to size needed. Plenty in the package for multiple projects)
Arduino Uno - if you don’t have one I would suggest getting an official board. I have had mixed luck with the unofficial versions.
Multi-meter which can measure resistance and also check for continuity
Jumper wires
Highly recommended but not absolutely required is a hands free magnifier as the TSSOP chips are very small. You will need both hands for soldering and testing with the multi-meter. I use a pair of Harbor Freight 3x Clip-On Magnifiers on top of my prescription glasses and a free standing\articulated magnifying glass. Other options are a pair of inexpensive readers from the discount or dollar store. You can even wear the readers over your prescription glasses or get two pairs of readers (one of top of the other) depending on how good (or bad) your vision is. If you are doubling up on glasses be careful as your range of vision will be very limited so make sure to take them off before doing anything else. Also be extra careful when soldering.
One other item that is not required but highly recommended is the Harbor Freight Helping Hands. They are alligator clips attached to a metal base. These are available from many other vendors on the internet as well under different brand names. These are very helpful when soldering the chip onto the breakout board.”

Link to article