BETALM4040A-grade 2.5 V shunt reference
A precise voltage reference with just two active connections.
LM4040 is a fixed shunt voltage-reference family. This page selects the A-grade 2.5 V industrial version: it holds the cathode near 2.5 V relative to the anode by sinking current supplied through an external resistor. It is a precision reference, not a power-supply regulator. The selected LM4040AIZ-2.5/NOPB in TO-92 and LM4040AIM3-2.5/NOPB in SOT-23 have different physical pin numbers. Both have only two active electrical connections; the third lead must float or connect to the anode. All package views and footprint downloads follow the selected version. Initial accuracy is ±0.1% at 25°C and 100 µA reference current. The industrial ambient range is −40 to 85°C. Budget at least 65 µA reference current for the full temperature range, stay below 15 mA in normal use, and account for load current and temperature drift.
