The ADS131M06-Q1 has two reference voltage options: the internal reference and an external reference. The internal reference uses a low-drift, band-gap voltage to supply the reference for the ADC. The internal reference has a nominal voltage of 1.2 V, allowing the differential input voltage to swing from –1.2 V to 1.2 V. The reference circuitry starts up very quickly to accommodate the fast start-up feature of this device. The device waits until after the reference circuitry is fully settled before generating conversion data. Do not place any capacitance on the REFIN pin if the current-detect mode is used. See the Section 8.4.6 section for more details about the current-detect mode.

The device also allows for an external reference voltage, which can be input at the REFIN pin. The nominal external reference voltage is 1.25 V. The full-scale range of the ADC is 1.2 V / gain when the reference voltage is 1.25 V. The ADC full-scale range maintains the ratio of 1.2 to 1.25 for all recommended reference voltages. For example, the ADC full-scale range is 1.248 V / gain if 1.3 V is applied to the REFIN pin instead of the nominal 1.25 V. The start-up time for the external reference is governed by the external circuitry.