Features and Benefits
- Register map is compatible with the AD7142
- On-chip RAM to store calibration data
- SPI-compatible (serial-peripheral-interface-compatible) serial interface (AD7147)
- I2C-compatible serial interface (AD7147-1)
- On-chip automatic calibration logic
Automatic compensation for environmental changes
Automatic adaptive threshold and sensitivity levels
- See datasheet for additional features
The AD7147 CapTouch™ controller is designed for use with capacitance sensors implementing functions such as buttons, scroll bars, and wheels. The sensors need only one PCB layer, enabling ultrathin applications.
The AD7147 is an integrated CDC with on-chip environmental calibration. The CDC has 13 inputs channeled through a switch matrix to a 16-bit, 250 kHz sigma-delta (Σ-Δ) converter. The CDC is capable of sensing changes in the capacitance of the external sensors and uses this information to register a sensor activation. By programming the registers, the user has full control over the CDC setup.
High resolution sensors require minor software to run on the host processor.
The AD7147 is designed for single electrode capacitance sensors (grounded sensors). There is an active shield output to minimize noise pickup in the sensor.
The AD7147 has on-chip calibration logic to compensate for changes in the ambient environment. The calibration sequence is performed automatically and at continuous intervals as long as the sensors are not touched. This ensures that there are no false or non-registering touches on the external sensors due to a changing environment.
The AD7147 has an SPI-compatible serial interface, and the AD7147-1 has an I2C®-compatible serial interface. Both parts have an interrupt output, as well as a GPIO. There is a VDRIVE pin to set the voltage level for the serial interface independent of VCC.
The AD7147 is available in a 24-lead, 4 mm × 4 mm LFCSP and operates from a 2.6 V to 3.6 V supply. The operating current consumption in low power mode is typically 26 μA for 13 sensors.
- Cell phones
- Personal music and multimedia players
- Smart handheld devices
- Television, A/V, and remote controls
- Gaming consoles
- Digital still cameras
Markets and Technologies
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Documentation & Resources
Capacitance-to-Digital Converter Facilitates Level Sensing in Diagnostic Systems4/1/2014 Analog Dialogue
ADI Capacitance-to-Digital Converter Technology in Healthcare Applications5/1/2012 Analog Dialogue
Designing Power Supplies for High Speed ADC2/1/2012
AC Shield Enhances Remote Capacitive Sensing5/1/2008 Analog Dialogue
Cooking Inductively: ADI iCoupler Technology Isolates the Hob and the User Interface3/1/2008 Analog Dialogue
Providing an Edge in Capacitive Sensor Applications12/1/2007 Analog Dialogue
Software & Systems Requirements
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.