ZHCSKD9 October 2019 ADS1235-Q1
PRODUCTION DATA.
The ADC requires a reference voltage for operation. The ADC allows two external inputs and the internal analog power supply as reference options. The reference voltage is selected by independent positive and negative multiplexers. The default reference is the 5-V analog power supply (AVDD – AVSS). Figure 44 shows the block diagram of the reference multiplexer.
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 selections are AVDD, REFP0 and AIN0 (REFP1). The negative reference input selections are internal AVSS, REFN0, AIN1 (REFN1). The reference low-voltage monitor is located after the reference multiplexer. See the Reference Monitor section for more information.