Dual 50k linear rheostat with I2C and non-volatile storage
The DS1859B-050+ is a dual-channel digital rheostat from Analog Devices, configured as two independent 50 kOhm variable resistors with 256 tap positions each, giving roughly 195 ohms per step resolution on a linear taper. The wiper position is stored in non-volatile memory, so the resistance setting survives power cycling — no need to re-initialize at every power-up. An on-chip temperature sensor and selectable I2C address let you read the die temperature over the same bus, reducing component count in a calibration or bias-adjustment loop.
Package and supply considerations for layout
The ±20 % resistance tolerance is typical for digital pots — the end-to-end value can vary by 10 kOhm from part to part, so the design should rely on the ratiometric tap accuracy, not the absolute resistance, for calibration.
Temperature range and drift
Rated for -40 °C to +95 °C operation, the DS1859B-050+ fits industrial enclosures and outdoor telecom cabinets where the ambient stays below 85 °C. The 50 ppm/°C temperature coefficient means the 50 kOhm end-to-end resistance drifts about 2.5 ohms per degree — negligible for most bias and trim circuits, but worth derating if the application spans the full -40 to +95 °C range.
Lifecycle and compliance status
RoHS3 compliant (2011/65/EU + 2015/863), with no restricted substances in the BOM.