Adjustable shunt reference in SOT-23-3
It is the low-voltage sibling of the industry-standard TL431, operating with a minimum cathode current of 80 µA — roughly one-tenth the TL431's requirement — which makes it suitable for battery-powered and low-quiescent bias circuits. The ±1% tolerance on the reference voltage suits precision power-supply feedback loops, voltage monitors, and isolated secondary-side regulation in telecom and industrial power converters.
Output current and cathode current limits
The shunt can sink up to 15 mA of continuous cathode current. This sets the upper bound for the series resistor value in a given supply rail — for a 5 V rail with a 1.24 V reference, the resistor must drop 3.76 V at 15 mA, so the minimum resistor is 250 Ω. The 80 µA minimum cathode current ensures the device stays in its linear region even at light load; below that threshold the reference voltage drifts outside the ±1% window.
The SOT-23-3 package (TO-236-3 / SC-59 compatible) occupies minimal board area and is a direct footprint match for the TL431 in the same package, easing a drop-in swap where the lower cathode current is needed.