What this digital pot is and where it fits
The Maxim Integrated DS1804U-050+ is a single-channel, 100-tap digital potentiometer with a linear taper and 50 kΩ end-to-end resistance. It stores the wiper position in non-volatile memory, so the setting survives power loss without a backup EEPROM. The part operates from a 2.7 V to 5.5 V supply and is specified over the industrial temperature range of -40°C to +85°C. Typical applications include calibration trim in power supplies, sensor offset adjustment, and volume control in audio equipment where the linear taper is preferred.
Linear taper and 100 taps — what they mean for the BOM
The linear taper means the wiper resistance changes uniformly with each tap position — every step moves the resistance by 500 Ω (50 kΩ ÷ 100). That is predictable and repeatable, which is exactly what a calibration technician wants when trimming a reference voltage or setting a comparator threshold. The 100-tap resolution gives about 0.5% of full-scale per step, adequate for coarse-to-medium adjustment. If your design needs finer granularity, you step up to a 256-tap part; if you only need a few fixed levels, a lower-tap-count device saves cost.
Non-volatile wiper — no separate memory needed
Because the wiper position is stored in non-volatile memory, the DS1804U-050+ powers up at the last-set tap. That eliminates the need for a microcontroller to reload a calibration constant from an external EEPROM on every boot. The interface is a simple three-wire up/down control (U/D, INC, CS) — no SPI or I²C overhead. The wiper resistance is 400 Ω typical, which matters when the pot is used as a rheostat: that 400 Ω adds to the end-to-end resistance and limits the minimum resistance you can set.
Package and temperature grade
The DS1804U-050+ comes in an 8-pin uMAX/uSOP surface-mount package (3.00 mm body width). The -40°C to +85°C temperature range covers industrial control, outdoor telecom, and automotive cabin environments. The temperature coefficient is 750 ppm/°C typical — not a precision reference, but adequate for trimming applications where the absolute accuracy is set by an external reference or where the drift is calibrated out in system.
Lifecycle and sourcing
The Maxim DS1804 family includes other resistance values in the same pinout — but no direct pin-compatible alternate from another manufacturer is listed in the official cross-reference.