Adjustable shunt reference — why the 1.233 V floor matters
That 1.233 V floor is the bandgap core voltage; below it the reference loses regulation, so the design must budget headroom above that threshold. The shunt topology means it behaves like a Zener — it sinks current from the supply through a series resistor, and the cathode current must stay above 80 µA to maintain regulation. For a 3.3 V rail feeding a 2.5 V reference, the series resistor drops the difference at the maximum load current of 12 mA.
The ±0.5% initial accuracy at 25 °C is the room-temperature spread you see first on the meter. That matters when the reference feeds a 12-bit ADC — the drift eats into the LSB budget.
SOT-23-3 package and Tape & Reel — board-fit and procurement notes
The SOT-23-3 (TO-236-3 / SC-59) footprint is a standard three-lead surface-mount package with 0.95 mm pitch.