4.096V precision reference — the ADC/DAC full-scale anchor
The REF5040AIDG4 from Texas Instruments is a series voltage reference that delivers a fixed 4.096V output — the classic full-scale voltage for 12-bit and 16-bit ADCs and DACs operating from a 5V rail. The 3µVp-p low-frequency noise (0.1 Hz to 10 Hz) keeps the noise floor low enough for 16-bit conversions without external filtering.
What the drift and noise specs mean for your error budget
At 8ppm/°C, the output shifts about 0.33 mV over a 100°C span — roughly 0.08% of the 4.096V output. For a 16-bit ADC with a 4.096V reference, that drift consumes about 5 LSBs of the total error budget. The 3µVp-p noise in the 0.1–10 Hz band is the flicker noise floor; it sets the practical resolution limit for low-frequency measurements. The 1.2mA supply current is the quiescent draw — the reference itself, not the load current.
Input range and output drive
Input voltage range is 4.296V to 18V — the 200 mV dropout above the output is the minimum headroom for regulation. The 10 mA output current can drive multiple ADC reference inputs or a small resistive divider; for higher loads, buffer the output. The series topology means no external resistor is needed, unlike a shunt reference.
The base product number REF5040 covers multiple tolerance and temperature grades; the AIDG4 suffix identifies the ±0.1% grade in an SOIC-8 package shipped in tube. For tape-and-reel, check the REF5040AIDGKT ordering code.