CN0326: Isolated Low Power pH Monitor with Temperature Compensation

CIRCUIT FUNCTION AND BENEFITS
The circuit shown in Figure 1 is a completely isolated low power pH sensor signal conditioner and digitizer with automatic temperature compensation for high accuracy. The circuit gives 0.5% accurate readings for pH values from 0 to 14 with greater than 14-bits of noise-free code resolution and is suitable for a variety of industrial applications such as chemical, food processing, water, and wastewater analysis.

This circuit supports a wide variety of pH sensors that have very high internal resistance that can range from 1 MΩ to several GΩ, and digital signal and power isolation provides immunity to noise and transient voltages often encountered in harsh industrial environments.

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