Automotive-grade 2.5 V shunt reference in SOT-23-3
The LM4040QDIM3X2.5/NOPB is an automotive AEC-Q100 qualified shunt voltage reference from Texas Instruments, delivering a fixed 2.5 V output with ±1% initial tolerance. It is designed for precision biasing and ADC reference applications in automotive electronics, industrial controls, and battery-powered systems where a stable, low-noise voltage rail is required.
What the current ratings mean for your circuit
The 15 mA output current capability sets the load-driving limit — this shunt reference can bias multiple op-amp inputs or a low-power ADC reference input without an external buffer. The 70 µA minimum cathode current is the quiescent floor: the series resistor must be sized so that the sum of the load current and the cathode current stays above 70 µA to maintain regulation. Below that threshold the output voltage drifts outside the ±1% window.
Noise and temperature drift — the so-what
Wideband noise is specified at 35 µVrms over 10 Hz to 10 kHz, which is low enough for a 10- or 12-bit ADC reference without additional filtering in most automotive sensor chains.
The three-pin footprint — cathode, anode, and no-connect — is shared across the LM4040 family, so a single PCB land pattern covers multiple voltage options.