The AD7156 delivers a complete signal processing solution for capacitive sensors， featuring an ultralow power converter with fast response time. The AD7156 uses an Analog Devices， Inc.， capacitance-todigital converter （CDC） technology， which combines features important for interfacing to real sensors， such as high input sensitivity and high tolerance of both input parasitic ground capacitance and leakage current. The integrated adaptive threshold algorithm compensates for any variations in the sensor capacitance due to environmental factors like humidity and temperature or due to changes in the dielectric material over time. By default， the AD7156 operates in standalone mode using the fixed power-up settings and indicates detection on two digital outputs. Alternatively， the AD7156 can be interfaced to a microcontroller via the serial interface， the internal registers can be programmed with user-defined settings， and the data and status can be read from the part. The AD7156 operates with a 1.8 V to 3.6 V power supply. It is specified over the temperature range of ?40°C to +85°C.