JAJSVI4 October 2024 ADS127L21B
PRODUCTION DATA
The VCM output is a bias voltage for the control input of the output common-mode of a fully differential amplifier (FDA). The bias voltage establishes the common-mode voltage for the ADC input signal. The VCM voltage is regulated to the mid-point of the AVDD1 – AVSS power supply. With many types of FDAs, the same common-mode voltage is provided when the common-mode control input is floated when the FDA and ADC use the same power supply. However, if the FDA and ADC power supplies have different values, bias the FDA common-mode voltage with the VCM voltage. If the VCM voltage is not used, leave the pin unconnected. The VCM output is enabled by the VCM bit of the CONFIG1 register.