2.048 V fixed reference — the ADC reference decision
The REF3020AIDBZT: Fixed 2.048 V output, ±0.2% tolerance. The 25 mA output current can drive the reference input of multiple ADCs or a single precision DAC without an external buffer.
75 ppm/°C drift — the temperature error budget
Temperature coefficient is 75 ppm/°C over the -40 to 125 °C operating range. The output voltage shift is 75 ppm/°C per degree Celsius.
Noise floor: 23 µVp-p low-frequency, 65 µVrms wideband
Noise is specified as 23 µVp-p from 0.1 Hz to 10 Hz and 65 µVrms from 10 Hz to 10 kHz. The low-frequency noise dominates in DC-coupled precision circuits — a 23 µVp-p flicker noise component is about 1.1 LSB on a 12-bit ADC at 2.048 V. The wideband noise matters for sampling rates above 10 kHz; the 65 µVrms figure is the integrated noise the ADC sees across its conversion bandwidth.
SOT-23-3 package — rework and layout notes
The REF3020AIDBZT comes in a SOT-23-3 package (also listed as TO-236-3 / SC-59). Three pins — input, output, ground. Surface mount.
The base product number REF3020 covers the family; the AIDBZT suffix specifies the SOT-23-3 package and tape-and-reel / cut-tape delivery. For dual-sourcing, the REF3020 family includes several grade and package variants — confirm the output voltage and tolerance match before substituting.