Ultra low power capacitance converter for proximity sensing

The AD7150 delivers a complete signal processing solution for capacitive proximity sensors, according to the IC’s producer, Analog Devices.
By Control Engineering Staff August 23, 2007

Norwood, MA— The AD7150 delivers a complete signal processing solution for capacitive proximity sensors, according to the IC’s producer, Analog Devices . The device uses capacitance to digital converter (CDC) technology, combining features that are important for interfacing to real sensors, such as a high input sensitivity and a high tolerance of both input parasitic ground capacitance and leakage current.

The part’s built-in integrated adaptive threshold algorithm compensates for any variations in sensor capacitance due to environmental factors like humidity and temperature, or to changes in the dielectric material over time.

By default, the device operates in standalone mode using the fixed power-up settings, and indicates detection on two digital outputs. Alternatively, the AD7150 can be interfaced to a microcontroller via I2C interface, the internal registers can be programmed with user-defined settings and the data and status can be read from the part.

The AD7150 operates from a 3.3 V power supply. It is specified over the temperature range of -40°C to +125°C.

—Edited by C.G. Masi , senior editor, Control Engineering