66.9.2 External Reference Voltage
VADVREF is an external reference voltage applied on the pin ADVREF. The quality of the reference voltage VADVREF is critical to the performance of the ADC. A DC variation of the reference voltage VADVREF is converted to a gain error by the ADC. The noise generated by VADVREF is converted by the ADC to count noise.
| Symbol | Parameter | Conditions | Min | Typ | Max | Unit |
|---|---|---|---|---|---|---|
| VADVREF | Voltage Range | Full operational | 2 | – | VDDANA | V |
| RMS Noise | Bandwidth 10 kHz to 1 MHz | – | – | 100 | µV | |
| RADVREF | Input DC Impedance | ADC reference resistance bridge(1) | 6 | 8 | 10 | kΩ |
| IADVREF | Current | VADVREF = 3.3V | – | – | 460 | µA |
Note:
- When the ADC is off, the ADVREF impedance has a minimum of 1 MΩ.