Fixed 2.048 V shunt reference — the BOM-fit anchor
The Texas Instruments LM4040C20QDBZRG4 is a precision shunt voltage reference delivering a fixed 2.048 V output with ±0.5% initial tolerance. It is designed for bias and reference circuits in ADC/DAC signal chains, power-supply feedback loops, and portable instrumentation where a stable, low-drift voltage is needed without a series regulator.
±0.5% tolerance and 100 ppm/°C drift — what they mean for accuracy
The ±0.5% initial tolerance sets the absolute accuracy at 25 °C; a 2.048 V reference will be between 2.037 V and 2.059 V at first power-up.
SOT-23-3 package — footprint and thermal reality
Housed in a three-pin SOT-23-3 (also listed as TO-236-3 / SC-59), the part occupies minimal board area. The shunt architecture means the cathode current (80 µA minimum) sets the operating point; the 15 mA maximum output current is derated by the package's thermal resistance — in practice, keep the cathode resistor sized so the device dissipates under 150 mW at 85°C ambient to stay within the SOT-23-3's power capability.