Analog and Interface Product Solutions Digital Potentiometers Design Guide Supporting digital potentiometer applications, including: mechanical potentiometer replacement, amplifiers with offset and trimming, band pass filtering with offset and gain trimming, programmable filter, Whetstone bridge trimming and general embedded system design techniques. Design ideas in this guide use the following devices. A complete device list and corresponding data sheets for these products can be found at www.microchip.com. MCP4011 MCP4021 MCP41010 MCP4012 MCP4022 MCP41050 MCP4013 MCP4023 MCP41100 MCP4014 MCP4024 MCP42010 MCP42050 MCP42100 www.microchip.com/analogDigital Potentiometer Solutions The serial interface options allow the designer to easily Microchips Family of Digital Potentiometers integrate the device into the application. For some Microchip offers a range of devices that allow the applications the simple Up/Down interface will be customer to select a device that is a best fit for their adequate, while for other applications the SPI interface will application. Some of the selection options include: better meet their system requirements. A wide range of resistor values The availability of both volatile and non-volatile devices RAB resistance (typical) from 2.1 k to 100 k allows the designer flexibility in optimizing the application. Step resolution Some applications may use the digital potentiometer as a replacement for a mechanical potentiometer. In this case, 6-bit a non-volatile device with the serial interface connecting to 8-bit the test hardware interface allows a low cost device with Serial Interfaces low cost manufacturing. Up/Down Resistor Network configurations allow the package size/ SPI cost to be minimized for the desired functionality. If a Memory Types variable resistor (rheostat) with one terminal tied Volatile to ground is desired, then only one resistor terminal Non-volatile (the wiper) needs to be implemented. In the MCP402X family, this configuration is shown in the MCP4024 and Resistor Network Configurations allows the functionality to be achieved in the low-cost Potentiometer (Resistor divider) SOT-23-5 package. The potentiometer pinout with all Rheostat (Variable resistor) terminals available requires an 8-pin package. Single/dual Potentiometer Options Dual potentiometer options allow the customer to have Package Options potentiometers/variable resistors that are closely matched Special Features in the system, since the two devices are on the same device die. Shutdown Mode WiperLock Technology Packaging options allow customers to address their system requirement trade-offs including device cost, Low Voltage, Low Power Options board area, and manufacturing sites (surface mount vs. Resistor sizes and resolutions allow the designer to thru-hole). Packages include tiny 3x3 SOT-23 and 3x2 DFN select the step resistance and number of steps. For the packages. device with the resistance (RAB) equal to 2.1 k, there are 64 steps (63 resistors), so the step resistance (RS) equals RAB/63 (or 33.33). Now at the other end of the spectrum, for the device with the resistance (RAB) equal to 50 k, there are 64 steps (63 resistors), so the step resistance (RS) equals RAB/63 (or 793.65). 2 Digital Potentiometer Design Guide