SBAS949A February 2020 – February 2021 ADS131M06
The ADS131M06 features an internal analog test signal that is useful for troubleshooting and diagnosis. A positive or negative DC test signal can be applied to the channel inputs through the input multiplexer. The multiplexer is controlled through the MUXn[1:0] bits in the CHn_CFG register. The test signals are created by internally dividing the internal reference voltage. The same signal is shared by all channels.
The test signal is nominally 2 / 15 × VREF. The test signal automatically adjusts its voltage level with the gain setting such that the ADC always measures a signal that is 2 / 15 × VDiff Max. For example, at a gain of 1, this voltage equates to 160 mV. At a gain of 2, this voltage is 80 mV.