1.225V shunt reference — the ±0.2% tolerance floor
The Texas Instruments LM4051BIM3X-1.2/NOPB is a precision shunt voltage reference that delivers a fixed 1.225 V output with an initial tolerance of ±0.2%. It operates as a shunt (two-terminal) reference, meaning it sinks current from a supply through a series resistor to regulate the output voltage — the same topology as a Zener diode but with far tighter accuracy and stability.
Noise floor and temperature drift
Wideband noise is specified at 20 µVrms over 10 Hz to 10 kHz, making this reference suitable for 12-bit ADC references or precision comparator thresholds where noise on the reference rail directly degrades conversion accuracy.
Current budget: 12 mA output, 65 µA cathode
The reference can source or sink up to 12 mA of output current — enough to bias a small load or feed the reference input of an ADC without an external buffer.
Housed in a three-lead SOT-23-3 package (also designated TO-236-3 / SC-59), this is a surface-mount part that fits a standard 0.95 mm pitch footprint.