JAJSGG2C October 2018 – June 2019 ADS125H02
Linear operation of the PGA requires that the absolute input voltage does not exceed the specified range. The following example shows how to verify the absolute input voltage is within the valid range. In this example, the input signal is ±10 V with an arbitrary 15% overrange capability. The negative input lead of the sensor is connected to AGND. The ADC gain is 0.1875 using a 2.5-V reference voltage and ±15-V power supplies with 5% voltage tolerance. The summary of conditions to verify the ADC range are:
The evaluation of Equation 5 (for gain < 1) results in:
–11.75 V < –11.5 V and 11.5 V < 11.75 V
The inequality is satisfied, and as a result, the absolute input voltage is within the ADC input range requirement.