5 V shunt reference with ±0.5% initial accuracy
The Texas Instruments LM4040CIM3X-5.0/NOPB is a precision shunt voltage reference that delivers a fixed 5 V output with a ±0.5% initial tolerance. The shunt topology means it operates like a two-terminal Zener — the load and the bias resistor share the same node, and the 80 µA minimum cathode current keeps the reference in regulation down to light loads. Output current capability is 15 mA, which covers the bias current for a typical ADC reference input or a comparator threshold divider.
SOT-23-3 footprint and supply routing
The SOT-23-3 (TO-236-3 / SC-59) package is a three-pin surface-mount footprint with 0.95 mm pitch. The cathode pin connects to the positive rail through the bias resistor; the anode pin goes to ground. The reference pin is the output — no separate feedback divider needed because the output is fixed at 5 V. The base product number LM4040 spans multiple voltage options and tolerance grades; the C grade in this code indicates the ±0.5% bin.