A/D converter circuit for direct drive capacitive input based on INA321/322 design

The following is a circuit diagram of an A/D converter circuit for direct capacitive input based on INA321/322 design.

As shown in the figure, this A/D converter uses a direct capacitive input configuration with INA321 or INA322. These amplifiers have a low output impedance, which allows them to directly drive capacitive loads during high-frequency operations. The input voltage is first amplified by the INA321/322 and then sent directly to a 12-bit high-speed, low-power sampling A/D converter such as ADS7818 or ADS7822. The internal input of these ADCs is a capacitor array (CDAC), making it a capacitive input stage. This design ensures accurate conversion of the analog signal into a 12-bit digital output, ideal for applications requiring precision and efficiency.

(Editor: Circuit Diagram)