4.096 V fixed shunt — the ADC reference anchor
That voltage is a natural fit for single-supply 12-bit and 16-bit ADCs where the reference input spans 0 V to 4.096 V — every LSB corresponds to exactly 1 mV (12-bit) or 62.5 µV (16-bit), simplifying the conversion math in firmware.
±1% tolerance — where it lands on the accuracy budget
The ±1% initial tolerance means the actual output at 25 °C sits between 4.055 V and 4.137 V. For a 12-bit ADC with a 4.096 V reference, that tolerance contributes roughly ±10 LSB of gain error before any temperature drift is factored in. If the system needs better than 0.5% accuracy without trimming, step up to the ±0.1% or ±0.2% grade in the same LM4040 family.
15 mA output — enough for multiple loads
The shunt can source or sink up to 15 mA while regulating. That covers biasing the reference input of two or three ADC channels plus a feedback divider on a switching regulator, all from one device. The minimum cathode current is 88 µA — below that the shunt drops out of regulation, so the series resistor must be sized to keep at least 88 µA flowing at the minimum input voltage.