By Andy Choi
Texas Instruments, a semiconductor solution provider headquartered in Dallas, Texas, has revealed two configurable analog front ends (AFE) designed to bridge the gap between the sensor and the microprocessor. The two AFEs developed by TI include the LMP91200 pH sensing AFE and the LMP91050 NDIR gas sensing AFE.
NDIR and pH Sensing AFEs
The integration of a single AFE into pH sensor and nondispersive infrared (NDIR) gas sensor platform allows design engineers to shorten the development time. The AFEs can be used in conjunction with the WEBENCH Sensor AFE Designer software and development system, allowing engineers to choose a sensor, configure the solution and download the data required for configuration, thus enabling faster prototyping.
The LMP91050 NDIR gas sensing AFE can support greenhouse gas monitoring, indoor CO2 monitoring, HVAC, demand control ventilation, alcohol breath analysis and Freon detection. It features a programmable gain amplifier, an adjustable common-mode generator, a SPI interface and a dark-phase offset cancellation circuitry. It features both high gain and low gain range, enabling the AFE to use thermopiles offering dissimilar sensitivities.
The LMP91200 pH sensing AFE has been designed to support two electrode pH sensors for steam and water quality monitoring, food processing, emissions monitoring and chemical/petrochemical plants. It features signal guarding, PGA, low input-bias pH buffer, common-mode generation, diagnostics circuitry and temperature and measurement calibration. An on-board sensor test guarantees proper functionality and connection. An ultra-low bias current of 0.4 pA ensures a high degree of accuracy and system reliability while safeguarding the pH electrodes in absence of supply.
The LMP91050 NDIR gas sensing AFE offers a small form factor of 3x4.9 mm, while the LMP91200 pH sensing AFE is available in 5x6.4 mm package.