What this adjustable shunt reference brings to the rail
Its 2.495 V minimum output is the starting point for setting any higher reference voltage with two external resistors. Output current is rated to 100 mA.
Setting the output voltage and what the tolerance means
The TL431ILPR's output is adjustable from the 2.495 V internal reference up to 36 V using a simple resistor divider from cathode to reference pin. The ±2.2% tolerance on the reference voltage translates directly into the set-point accuracy of your regulated rail — a 5 V output will sit within about ±110 mV of the target at 25°C, with additional drift from the resistor divider. For a precision 3.3 V rail feeding an ADC reference, that may be acceptable; for a tighter band, step to a lower-tolerance grade in the TL431 family. The 1 mA minimum cathode current must be maintained to keep the device regulating — if the external load drops too low, add a pull-down resistor to ground.
The TO-92-3 package with formed leads is a through-hole part that fits standard prototyping boards and legacy PCB layouts.
Lifecycle and sourcing decision
It is ROHS3 compliant. No last-time-buy risk on the horizon for this standard catalog part.