JAJSGG2C October 2018 – June 2019 ADS125H02
The options for the ADC reference voltage are the internal 2.5-V reference, two external reference sources, or the AVDD power supply. The reference voltage is differential and is defined by: VREF = (VREFP – VREFN), where VREFP and VREFN are the positive and negative reference voltages. The polarity of VREF must always be positive. Figure 61 illustrates the block diagram of the reference input multiplexer used to select the reference.
Program the RMUXP[1:0] and RMUXN[1:0] bits of the REF register to select the positive and negative reference voltages, respectively. The positive reference options are internal 2.5-V positive, external REFP0, external REFP1, or AVDD. The negative selections are internal 2.5-V negative, external REFN0, external REFN1, or AGND.
The reference voltage is internally monitored for a low-voltage condition; see the Reference Monitor section.