8.192 V shunt reference — the precision anchor
Its primary job is to provide a stable, accurate voltage for ADC/DAC references, comparator thresholds, or precision regulator feedback dividers in systems that need better than a Zener's raw breakdown. The ±0.5% initial tolerance means this grade suits 12-bit ADC references without external trim — the reference error stays under one LSB for a 12-bit converter spanning 0–8.192 V. For a 10-bit system the headroom is even wider. That's tight enough for industrial sensor interfaces where the reference must track the ADC's own drift.
Shunt topology — two-terminal simplicity
As a shunt reference, the LM4040C82IDBZR behaves like a precision Zener: it sits in parallel with the load and draws current through a series resistor from the supply rail. The cathode current floor is 110 µA, and the device can sink up to 15 mA continuous. The series resistor must be sized so the cathode current never drops below 110 µA at minimum supply and maximum load current, and never exceeds 15 mA at maximum supply and minimum load. Output noise is 130 µVrms over the 10 Hz to 10 kHz band — low enough that it won't dominate the noise floor of a 12-bit ADC with a 8.192 V reference. For 16-bit systems, a post-filter or a lower-noise reference grade may be needed.
SOT-23-3 — board-area fit and thermal limits
The SOT-23-3 package (also listed as TO-236-3 / SC-59) is a three-lead surface-mount footprint. It fits tight layouts but the junction-to-ambient thermal resistance limits power dissipation. Store the reels dry — SOT-23-3 is not moisture-sensitive per JEDEC Level 1, but the carrier tape can absorb humidity in long-term storage.
The base product number is LM4040, and the family includes multiple voltage options and tolerance grades in the same SOT-23-3 footprint.