The Maxim Integrated DS1804U-050+T&R is a single-channel, 100-tap, non-volatile digital potentiometer with a linear taper and 50kΩ end-to-end resistance. It stores the wiper position in on-chip EEPROM, so the setting survives power cycles — no re-calibration after a brownout or field power-down. The 2.7V to 5.5V supply range lets it run off a 3.3V or 5V rail without a separate regulator.
With 100 tap positions and a linear taper, each step changes the resistance by about 500Ω nominal (50kΩ / 100). The wiper resistance is 400Ω typical, which matters at the low end of the range: the first few taps will show a floor of about 400Ω plus the tap resistance, so don't expect a true zero-ohm wiper-to-B connection.
Package and field-swap reality
It comes in an 8-uMAX/uSOP package (3.00mm body width, 0.118" pitch) — small enough for dense boards, but the lead pitch is still hand-solderable with a fine-tip iron and a loupe. No hot-air station required if you're careful.