Fixed 2.5V shunt reference — what the ±1.5% tolerance buys you
The Texas Instruments LM385BXMX-2.5/NOPB is a shunt voltage reference that delivers a fixed 2.5V output with a ±1.5% initial tolerance. It is the sort of part you reach for when an ADC's internal reference drifts too much or a comparator threshold needs a known anchor — think power-supply monitoring, data-acquisition front ends, or setting the trip point on an overvoltage latch. The 8-SOIC package fits into a compact analog signal chain without dominating board area.
20 mA output, 20 µA cathode — sizing the bias resistor
A shunt reference works by sinking current through a series resistor from the supply rail. The LM385BXMX-2.5/NOPB can sink 20 mA continuously, which means the resistor value must keep the current between the 20 µA minimum cathode current and that 20 mA ceiling across the full input voltage range. If your load draws 5 mA and the supply swings from 5V to 24V, you size the resistor so the shunt always has enough headroom to regulate. The 120 µVrms noise spec (10 Hz to 10 kHz) is low enough for a 10-bit or 12-bit system, though a 16-bit precision chain would want a lower-noise bandgap reference.
Active production — no LTB on the horizon
The part ships on Tape & Reel, which suits automated pick-and-place assembly lines.