Integrated AFE for Low-Power pH Sensing Applications

The LMP91200 device is a sensor AFE for use in low-power, analytical-sensing applications. The LMP91200 is designed for 2-electrode sensors. This device provides all of the functionality needed to detect changes based on a delta voltage at the sensor. Optimized for low-power applications, the LMP91200 works over a voltage range of 1.8 V to 5.5 V. With its extremely low input bias current it is optimized for use with pH sensors. Also, in absence of supply voltage the very low input bias current reduces degradation of the pH probe when connected to the LMP91200. Two guard pins provide support for high parasitic impedance wiring. Depending on the configuration, total current consumption for the device is 50 µA while measuring pH. Available in a 16-pin TSSOP package, the LMP91200 operates from –40°C to +125°C.