5 V shunt reference in a SOT-23-3 footprint
Packaged in a SOT-23-3 surface-mount case, it is designed for industrial temperature environments spanning -40°C to 85°C.
Noise and drift — the precision floor
The reference exhibits 80 µVrms noise over the 10 Hz to 10 kHz band, and a temperature coefficient of 100 ppm/°C. For a 5 V rail, that drift translates to roughly 0.5 mV per °C — a figure that matters when the ADC reference or comparator threshold needs to stay tight across temperature.
Shunt operation and cathode current budget
As a shunt reference, the LM4040B50IDBZRG4 regulates by sinking current through its cathode. The minimum cathode current is 95 µA, and the maximum continuous output current is 15 mA. Design the series resistor to keep the cathode current within that window across the full load and supply range — too little current and the reference drops out of regulation; too much and it self-heats past the 85°C ceiling.