Linear taper, 128 taps, non-volatile wiper
The MAX5128ELA+T is a single-channel digital potentiometer from Analog Devices with a linear taper, 22kΩ end-to-end resistance, and 128 wiper tap positions. The non-volatile memory type means the wiper position is stored at power-off and recalled on the next power-up — no need to re-initialise the setting after a cycle.
Package and hand-solderability
Housed in an 8-WFDFN package with a supplier device package of 8-µDFN measuring 2x2 mm. The exposed pad underneath is the thermal and electrical ground connection — a short PCB trace to the ground plane keeps the thermal resistance low. No breakout board needed for a prototype — just a small adapter PCB or dead-bug wiring.
Interface and wiper resistance
The interface is Up/Down (UP, DN) — a two-wire control that increments or decrements the wiper one tap per pulse. This is simpler than SPI or I²C for applications that only need occasional adjustment, like a volume control or a programmable reference voltage. The wiper resistance is 600Ω typical, which adds a small series resistance in the signal path — factor it into the divider ratio calculation if the load impedance is below 100kΩ. Temperature coefficient is 50 ppm/°C typical, so the resistance drifts about 1.1Ω per °C at 22kΩ — negligible for most bias and audio circuits.