Shunt reference for the 2.5 V rail
The LM385BPWR-2-5 is a 2.5 V fixed-output shunt voltage reference from Texas Instruments, in the 8-TSSOP surface-mount package. It delivers up to 20 mA output current while the cathode current sits at 20 µA — the shunt architecture means it regulates by shunting current away from the load, so the series resistor sets the total current budget.
Noise floor and signal-chain fit
For a 12-bit ADC with a 2.5 V reference, that noise contributes roughly 0.2 LSB of uncertainty at the converter's full-scale, which is acceptable for most industrial data-acquisition and control loops but worth derating for a 16-bit design targeting better than 14 ENOB.
Tape & Reel packaging feeds directly into pick-and-place; Cut Tape is also available for prototype or low-volume builds.