Shunt reference in a SOT-23-3 — what this part does
The Texas Instruments LM4041EIM3X-1.2 is a precision shunt voltage reference that delivers a fixed 1.225 V output with ±2 % tolerance. It operates as a two-terminal device — the cathode current sets the reference voltage across the load, and the part regulates by shunting excess current to ground. With a cathode current of just 65 µA and a maximum output current of 12 mA, it fits low-power bias and ADC reference applications where board space is tight.
1.225 V at ±2 % — what the tolerance buys you
The ±2 % initial accuracy on the 1.225 V output means the reference voltage can sit anywhere between roughly 1.200 V and 1.250 V at 25 °C. For an 8-bit ADC with a 1.225 V reference, that translates to about ±5 LSB of full-scale uncertainty before any temperature drift is factored in. If your design needs tighter than 2 % initial accuracy, you will want to look at the A-grade or B-grade variants in the LM4041 family, or move to a series reference like the LM4132.
Temperature drift and noise floor
Noise from 10 Hz to 10 kHz is specified at 20 µVrms — low enough for most 12-bit ADC references but worth budgeting for in a 16-bit system.
The three-pin footprint is compact — roughly 2.9 mm by 1.3 mm — and the shipping options include Tape & Reel and Cut Tape.