±2.2% tolerance — what it means for regulation accuracy
The TL431IDBVRG4 is an adjustable shunt reference with a ±2.2% tolerance on the 2.495 V internal reference. For a 5 V output rail, that translates to roughly ±110 mV of initial accuracy before temperature drift — tight enough for most linear regulator feedback dividers, ADC references, and comparator thresholds. If your design requires better than ±1%, step up to the TL431A or TL431B grade variants.
100 mA output current — driving the load budget
The shunt regulator can sink up to 100 mA continuous, which sets the ceiling for the cathode resistor and the load it can regulate. In a typical shunt configuration, the cathode resistor must be sized so that the sum of the load current and the 1 mA minimum cathode current stays below 100 mA across the full input voltage range. Exceed that and the reference voltage drifts out of regulation.
SOT-23-5 — rework and layout notes
The SOT-23-5 package (SC-74A body, 5 leads) is a surface-mount footprint that reworks cleanly under hot air with a 300°C profile — the small thermal mass means it lifts without cooking adjacent components. The pinout is standard for the TL431 family: cathode, anode, reference, and two NC pins. Keep the cathode trace short to minimise parasitic inductance that can cause oscillation at high shunt capacitance.