Intelligent sensor devices combine low power and small size

21st November 2006

Analog Devices

ES Admin

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Analog Devices is expanding its capacitance-to-digital converter (CDC) and iSensor intelligent sensor families with new devices that deliver a combination of high sensitivity, low power, low cost and small size for sensing applications. The new CDC device provides superior power efficiency, sensitivity, response time, and robustness in proximity sensing applications, such as automotive remote keyless entry systems. Based on Analog Devices' iMEMS inertial sensor cores, the highly integrated, and pre-calibrated, iSensor intelligent sensor devices provide a simplified programmable interface and are designed for embedded motion analysis and control applications.

Discrete sensors have a history of being expensive and difficult to implement, said Mike Britchfield, product line director, Precision Signal Processing, Analog Devices. ADI's CDC and iSensor device families break down the barriers that have kept designers from adding sensing functions to their system designs due to cost and excessive power consumption.

Analog Devices today is expanding its portfolio of CDCs for sensor systems with the introduction of a new family of ultra-low-power devices specifically designed for highly sensitive proximity sensing applications. Leveraging ADI's industry-leading capacitance technology, the AD7150 delivers a complete signal processing solution for proximity sensors, offering important features such as electromagnetic compatibility (EMC), adaptive environmental calibration, small package, low power consumption and fast response time.

Unlike existing solutions that use optical sensors, which can be unreliable and power hungry, the AD7150 consumes just 90 µA, resulting in a 70 percent power savings. The AD7150 is ideal for use in portable and battery-powered products in automotive, industrial and even consumer applications, such as entry and security systems, remote detection and contact-less switches.

The AD7150 has undergone extensive EMC evaluation, making it particularly suitable for use in the harsh environments experienced in today’s demanding automotive and industrial applications. In addition, ADI’s patented CDC front-end architecture makes the AD7150 tolerant of input parasitic ground capacitance, leakage currents and power supply noise. This greatly enhances the implementation of robust and highly sensitive proximity sensor systems that provide consistent detection every time.

The highly robust and sensitive proximity sensor system is further enhanced by the on-chip adaptive environmental calibration feature. This enables the device to automatically recalibrate and adapt to capacitance changes due to shifts in environmental conditions, such as temperature, humidity, and the gradual build-up of dust and dirt.

In addition to the AD7150, which has two channels, Analog Devices is announcing the availability of the AD7151, a single-channel CDC that consumes only 50 µA. Both devices are specified over a –40°C to +125°C temperature range and communicate over an I²C serial interface. Automotive qualified models will be available on release.