3 V shunt reference in a SOT-23-3 — what it delivers
Tolerance, noise, and bias current — the decision specs
The ±2% initial tolerance (E grade) is adequate for general-purpose ADC references and comparator thresholds; for tighter accuracy, the A-grade (0.1%) or B-grade (0.2%) siblings in the LM4040 family are the next step up. Output noise is 35 µVrms over 10 Hz to 10 kHz, clean enough for a 12-bit SAR ADC without additional filtering. Minimum cathode current is 70 µA — the shunt must see at least this much bias current to regulate.
The SOT-23-3 footprint is a standard three-pin layout shared with many shunt references, making it a drop-in candidate for existing board designs. The temperature coefficient is 150 ppm/°C — a moderate drift that is acceptable for 8- to 12-bit systems but may need calibration or a tighter-tempco part for 14-bit or above.