Ultra-Low Power, 1-Channel, Capacitance Converter for Proximity Sensing

The AD7151 delivers a complete signal processing solution for capacitive proximity sensors, featuring an ultra-low power converter with fast response time. The AD7150 is a two-channel alternative to the AD7151.

The AD7151 uses Analog Devices, Inc., capacitance-to-digital 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 AD7151 operates in standalone mode using the fixed power-up settings and indicates detection on a digital output. Alternatively, the AD7151 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 AD7151 operates with a 2.7 V to 3.6 V power supply. It is specified over the temperature range −40°C to +85°C.

APPLICATIONS

* Proximity sensing

* Contactless switching

* Position detection

* Level detection

* Ultra-low power

2.7 V to 3.6 V, 70 µA

* Response time: 10 ms

* Adaptive environmental compensation

* 1 capacitance input channel

Sensor capacitance (CSENS) 0 up to 13 pF

Sensitivity to 1 fF

* EMC tested

* 2 modes of operation

Standalone with fixed settings

Interfaced to a microcontroller for user-defined settings