Dual 100k digital pot with SPI control
The MAX5415EUD+ is a dual-channel digital potentiometer from Analog Devices, each channel offering 100k resistance with 256 tap positions — effectively an 8-bit resolution per channel for setting voltage dividers or variable resistors in analog signal chains. Communication runs over an SPI interface, and the wiper setting is volatile — the register resets to mid-scale on power-up and loses the setting when supply is removed, so the host must re-initialise the wiper position after each power cycle.
Resistance accuracy and temperature stability
The end-to-end resistance tolerance is ±25%, which is typical for semiconductor-based digital pots — the absolute value varies from lot to lot, but the ratiometric accuracy between taps within a single device is much tighter, making the part suitable for divider applications where the ratio matters more than the absolute resistance. Wiper resistance is 275 ohms typical — this adds a series offset at the wiper terminal that matters most at the low end of the resistance range, where the wiper-to-B resistance approaches the wiper resistance itself.