Adjustable shunt reference with ±2.2% tolerance
It provides a programmable output voltage from 2.495 V up to 36 V using two external resistors, with a typical output impedance of 0.2 Ω. The ±2.2% tolerance on the reference voltage is tighter than the standard TL431's ±2% grade, making this variant a better fit for precision regulation loops in power supplies, isolated converters, and battery chargers where output accuracy matters. Rated for a continuous cathode current of 100 mA, the device can directly drive optocoupler LEDs or small loads without an external transistor, simplifying the BOM in flyback and forward converter feedback circuits.
Industrial temperature grade and SOT-23-3 footprint
The SOT-23-3 package (TO-236-3) is a standard footprint for low-power references, with good thermal dissipation for the 100 mA output capability. The minimum cathode current of 1 mA ensures stable regulation across the full load range, and the device is fully specified for shunt operation from 1 mA to 100 mA.
The base product number TL431 spans multiple package and tolerance variants. For dual-sourcing, the standard TL431BIDBZR (1% tolerance) is a direct pin-compatible alternative if tighter accuracy is needed.