What this digital pot does in the circuit
The Maxim Integrated DS1804U-010+ is a single-channel, 10 kΩ digital potentiometer with 100 wiper taps and a linear taper. It stores the wiper position in non-volatile memory, so the setting is retained after power is removed — useful for calibration trims, offset nulling, or volume control in equipment that must remember its state at next power-on. The 100-tap resolution gives roughly 100 Ω per step, fine enough for most analog trimming tasks where a mechanical trimmer would drift or need manual adjustment.
Supply rails and temperature range
Runs from a 2.7 V to 5.5 V supply, so it works directly on a 3.3 V or 5 V rail without a separate regulator. The -40°C to 85°C operating range covers industrial environments — factory automation, outdoor telecom, and test equipment — but not under-hood automotive or extended high-temp zones. The 750 ppm/°C temperature coefficient on the end-to-end resistance is typical for a CMOS digital pot; if the application needs tight tracking across temperature, budget for that drift in the system error budget.
Package and rework considerations
Housed in an 8-pin uMAX/uSOP (3 mm body width), the DS1804U-010+ is a small-outline surface-mount part. The 0.118-inch (3.00 mm) width package is fine for hand rework with a hot-air station — the leads are visible and accessible. No exposed pad, so no thermal-via stitching needed. Standard MSL 3 handling applies: bake before reflow if the moisture-barrier bag has been open past the floor-life window.
Interface and control
Controlled via a 3-wire up/down interface: Chip Select (CS), Increment (INC), and Up/Down (U/D). This is a simple serial protocol — no I²C or SPI overhead — so any microcontroller with spare GPIOs can drive it. The wiper moves one tap per INC pulse when CS is low; the direction is set by the U/D pin level. This interface style is common in panel-trim applications where a pushbutton or encoder replaces a pot knob.
Lifecycle and sourcing
The DS1804U-010+ is listed as Active on the manufacturer's status and is ROHS3 compliant. No last-time-buy or end-of-life notice has been issued. For dual-sourcing or a pin-compatible alternate, the DS1804U-050+ (50 kΩ version) shares the same package and pinout — the only difference is the resistance value, so the 10 kΩ variant is the one for this BOM line.