50kΩ linear digital rheostat with I²C and non-volatile storage
The Maxim Integrated MAX5434LEZT+T is a single-channel, 50kΩ digital rheostat with 32 wiper tap positions and a linear taper. It is configured as a rheostat (two-terminal variable resistor), controlled over an I²C serial interface. The non-volatile memory stores the wiper setting at power-off, so the resistance value is restored on next power-up without host intervention — useful for calibration trims, adjustable bias networks, or volume control in equipment that must retain its setting through a power cycle.
What the ratings mean for the BOM
The 50kΩ end-to-end resistance with ±25% tolerance means the absolute resistance between the two rheostat terminals can vary across units. That is typical for a digital pot — the part is not a precision resistor. The design should rely on the ratiometric accuracy between tap positions (the linearity of the internal resistor string), not the absolute ohmic value. The 32 taps give a resolution of about 1.6kΩ per step on a 50kΩ scale, which is coarse enough for bias trim or level-setting but too coarse for fine-grain attenuation control. Wiper resistance is 610Ω (typical), which adds a fixed series offset at the zero-scale tap position — account for it in the minimum resistance path. The 35ppm/°C temperature coefficient on the resistor string is stable enough for industrial environments; the wiper resistance itself will drift more, but that offset is usually negligible in a rheostat configuration.
Temperature grade and environment
Rated for -40°C to 85°C operation, the MAX5434LEZT+T suits industrial control cabinets, outdoor telecom enclosures, automotive cabin electronics (non-engine-bay), and HVAC sensor-trim circuits. The 35ppm/°C tempo ensures the resistance ratio stays consistent across the temperature span, which matters for a calibration trim that must hold over a factory floor's seasonal swing.
Lifecycle and sourcing reality
ROHS3 compliant. The part is available through independent distribution; pricing and availability are confirmed at quote time against an RFQ.