The device features an internal reference source with a nominal output value of 2.5 V. On power-up, the internal reference is disabled by default. To enable the internal reference, set EN_REF = 1b in the GENERAL_CFG register. A minimum 1-µF decoupling capacitor is recommended to be placed between the REF and GND pins. The capacitor must be placed as close to the REF pin as possible. The REF pin has ESD protection diodes connected to the AVDD and GND pins.