2.5V shunt reference — ±0.1% initial accuracy in SOT-23-3
The LM4050AIM3-2.5+ is a precision micropower shunt voltage reference from Analog Devices, delivering a fixed 2.5 V output with ±0.1% initial tolerance and a 50 ppm/°C temperature coefficient.
Noise and drift — the signal-chain budget
Output noise is specified at 41 µVrms integrated from 10 Hz to 10 kHz — this is the wideband noise floor that sets the usable resolution for a 12- or 16-bit SAR ADC sampling at moderate rates. The 50 ppm/°C drift means the output shifts roughly 0.125 mV over a 25°C ambient swing — well within the LSB budget of a 12-bit ADC with a 2.5 V reference, but worth calculating for a 16-bit system aiming at 15 µV/LSB.
SOT-23-3 footprint and shunt topology
Housed in a standard SOT-23-3 (TO-236-3 / SC-59) surface-mount package, the part mates with a three-pin footprint — anode, cathode, and no-connect — and requires no output capacitor for stability, though a 0.1 µF bypass at the load side is typical practice. As a shunt reference, the LM4050AIM3-2.5+ sinks current through an external series resistor; the 65 µA minimum cathode current ensures the internal bandgap is biased correctly even at zero load.