JAJU878 November 2022 ADS117L11 , ADS127L11
The sensor is connected to the signal chain through a capacitor followed by a series resistor forming a high-pass filter, which has a cutoff of less than 1 Hz.
The resistor is forming a potential divider with a gain 10 to 1, reducing the input signal of ±10 V to ±1 V.
The resistor is referenced to mid-scale (2.5 V) instead of to ground to shift the signal.
A non-inverting gain stage is buffering and amplifying the signal to ±2 V + 2.5 V at the input of the fully-differential amplifier stage.
The dual op amp OPA2320 device is used for gain stage, and common-mode buffer. An op amp with an output swing reaching to 0.5 V from supplies is needed for that stage. A linear amplifier that does not suffer from crossover distortion is essential for good THD performance.