1.225 V shunt reference — precision for the bias rail
The Texas Instruments LM4041AIM3X-1.2/NOPB is a fixed 1.225 V shunt voltage reference in a three-pin SOT-23-3 package. It delivers a ±0.1% initial tolerance and a 100 ppm/°C temperature coefficient, making it suitable for precision ADC references, comparator thresholds, and regulator feedback dividers where the 1.225 V bandgap voltage is the natural setpoint.
65 µA cathode current — low-power bias budget
The minimum cathode current of 65 µA sets the lower bound for the series resistor value. In a 3.3 V rail application, a 32 kΩ resistor biases the reference at roughly 65 µA, keeping total reference power under 0.2 mW. The 12 mA maximum output current handles the load of driving an ADC reference input or multiple comparator inputs without an external buffer.
The 20 µVrms noise (10 Hz to 10 kHz) is low enough for a 12-bit ADC reference without additional filtering in most applications.