1.225 V shunt reference — error budget and drift
The Texas Instruments LM4041EIM7X-1.2/NOPB is a precision shunt voltage reference delivering a fixed 1.225 V output with a ±2% initial tolerance. As a shunt (two-terminal) reference, it operates like a low-drift Zener diode, sinking current through a single external series resistor — no separate supply rail needed.
12 mA output and 65 µA cathode current — drive limits
The reference can sink up to 12 mA of output current while maintaining regulation — this sets the maximum load the shunt can drive. The minimum cathode current is 65 µA, below which the reference may drop out of regulation. Design the series resistor to keep the total current (load plus reference quiescent) between 65 µA and 12 mA across all operating conditions. The 20 µVrms noise over 10 Hz to 10 kHz is low enough for 12-bit ADC references; for 16-bit or higher resolution, add a simple RC filter at the output.
SC-70-5 package — footprint and thermal reality
The SC-70-5 (SOT-353) package measures 2.0 mm × 2.1 mm with a 0.65 mm pin pitch. Surface-mount assembly requires a standard lead-free reflow profile; the small pad geometry limits power dissipation to what the 12 mA output allows. The package is RoHS-compliant and lead-free per the NOPB suffix.
No official second-source or direct replacement is listed; the LM4132AMF-4.1/NOPB is a series-reference part with tighter tolerance (0.05%) and a different topology, not a pin-compatible substitute.