The LM4120IM5-5.0 is a series voltage reference from Texas Instruments that outputs a fixed 5 V with ±0.5% initial accuracy. That tolerance is tight enough to bias an 8- or 10-bit ADC's Vref pin without external trimming, but for a 12-bit converter the 0.5% error eats about 20 LSBs of the input range — budget that into your system accuracy calculation. For a 5 V rail feeding a 10-bit ADC, that's under 0.5 LSB of drift — acceptable for most control loops. If your design sees wider temperature swings or needs 12-bit stability, look at the LM4120's tighter-graded siblings (0.2% or 20 ppm variants).
Noise floor and output drive — where the part fits in the signal chain
That's clean enough for a 16-bit SAR ADC reference — the noise contribution at 5 V output is roughly 0.3 LSB on a 16-bit converter with a 5 V span. For a 24-bit delta-sigma ADC, you'd want a lower-noise reference like the REF5050. Output current is rated at 5 mA maximum. That drives a handful of op-amp Vref inputs or a single ADC reference pin, but don't plan on powering external loads — the 275 µA quiescent supply current is the reference's own draw, and the output stage isn't designed for bulk current delivery. If your load exceeds 5 mA, buffer it with an op-amp or pick a higher-current reference.