Sensor interface analog front end simplifies sensor conditioning

The latest addition to Exar's family of analog front end sensor interfaces integrates high channel count and functionality in a tiny 3.5mm x 3.5mm footprint. The XR18910 provides 14-bit signal path linearity and is designed to connect analog sensors to a microcontroller (MCU) or field-programmable gate array (FPGA) with an embedded ADC.? The onboard 10-bit DAC offers ±560mV of offset correction and allows an independent offset value for each of the eight differential inputs. The programmable gain instrumentation amplifier offers eight fixed-gain settings (from 2V/V to 760V/V), ensuring the amplified sensor signal falls within the optimum input range of the downstream ADC. The integrated LDO provides a regulated 3V or 2.65V voltage to power the sensors. The XR18910 is controlled via an I2C serial interface and typically consumes 457µA of supply current and offers a sleep mode which reduces the supply current to only 45µA. “The XR18910 provides designers with an easy-to-use sensor interface that calibrates and amplifies signals from eight different analog sensors, improving overall system sensitivity and accuracy,” said Dale Wedel, vice president, high-performance analog, Exar. “It offers more functionality with lower power than discrete solutions and is suitable for a variety of applications such as force sensing, pod racers and power monitoring for solar energy and data centers. It also occupies a significantly smaller footprint than our original XR10910 16:1 sensor interface, making it more attractive when fewer channels are required.” The XR18910 is available in a RoHS-compliant, green/halogen free, space-saving 3.5mm x 3.5mm QFN package.