2.048V reference with 8ppm/°C drift — the noise floor you actually get
The MAX6071BAUT21+T is a 2.048V series voltage reference from Analog Devices, packaged in a SOT-23-6. Its ±0.08% initial tolerance means the output sits between 2.0464V and 2.0496V at 25°C — tight enough for a 16-bit ADC without external trimming, but you still budget the tempco for the full range. The 8ppm/°C temperature coefficient shifts the output about 1.6 mV over the -40°C to 125°C industrial range. That is the dominant error term in most precision signal chains — the initial tolerance gets calibrated out at board test, but the drift is baked into the reference's own silicon.
For a 16-bit ADC with a 2.048V reference, the noise contribution from the reference alone sits below 0.5 LSB — the ADC's own noise floor and the input signal's SNR will dominate the system noise budget, not this part. The 260 µA supply current is the quiescent cost of that stability — it is not a micropower part, but for a precision channel that stays powered, the draw is acceptable.