2.495 V shunt reference — the TL431AILPM in precision bias and regulation
The TL431AILPM is a three-terminal adjustable shunt voltage reference from the TL431 family, with a fixed minimum output of 2.495 V and a ±1% tolerance that marks the 'A' grade bin. The shunt regulator topology means it sinks current through the cathode to ground, regulating the voltage at the reference pin. With a 100 mA output current capability and a 700 µA minimum cathode current for regulation, it covers the common bias range for optocoupler feedback loops, secondary-side regulation in isolated supplies, and precision comparator thresholds.
Through-hole TO-92-3 — board-level fit and assembly
The TO-92-3 (TO-226AA) through-hole package with formed leads is a standard three-lead transistor outline. The formed leads suit wave-solder assembly or manual insertion for prototype and low-volume builds. This covers outdoor telecom cabinets, factory-floor sensor supplies, and automotive cabin environments — not the under-hood 125°C tier, but the common extended-temperature band for most non-engine-bay designs.
The base product number is TL431, so any PCN or EOL communication from Texas Instruments will reference the TL431 family. The 'A' suffix selects the ±1% initial tolerance bin; the 'ILPM' suffix encodes the package (TO-92-3) and the tape-and-box / cut-tape shipping format.