1.8V fixed output, 0.5% initial tolerance — the SOT-23-5 reference for precision bias rails
The LM4128CMF-1.8/NOPB is a series voltage reference from Texas Instruments that delivers a fixed 1.8V output with ±0.5% initial tolerance. It operates from a 2.2V to 5.5V input rail and can source up to 20 mA to the load.
Industrial temperature range and low drift — stable across the board
For a 1.8V output, that translates to roughly 180 µV of drift per degree — the dominant error term in a precision ADC front-end after the initial tolerance is trimmed out. The series architecture means the output capacitor is stable with any value from 0.1 µF to 10 µF, and the reference does not require an external resistor to set the output — the fixed-voltage variant simplifies the BOM to one bypass cap.
SOT-23-5 footprint — board integration and sourcing
Housed in a 5-pin SOT-23 (SC-74A) package, the LM4128CMF-1.8/NOPB occupies roughly 3 mm × 3 mm of board area. The small footprint and surface-mount assembly suit compact mixed-signal designs where a reference must sit close to the converter without routing a long analog trace.