Features and Benefits
- Programmable capacitance-to-digital converter (CDC) - Please see data sheet for additional information.
- On-chip automatic calibration logic
Automatic compensation for environmental changes
Automatic adaptive threshold and sensitivity levels
- Register map is compatible with the AD714x
- On-chip RAM to store calibration data
- SPI-compatible (serial-peripheral-interface-compatible) interface (AD7147A)
- I2C-compatible serial interface (AD7147A-1)
- Separate VDRIVE level for serial interface
- 25-ball, 2.3 mm × 2.1 mm WLCSP
- Low latency from touch to response
The AD7147A 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 AD7147A is an integrated CDC with on-chip environmen-tal 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 and may require two PCB layers.
The AD7147A is designed for single electrode capacitance sensors (grounded sensors). There is an active shield output to minimize noise pickup in the sensor.
The AD7147A 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 nonregistering touches on the external sensors due to a changing environment.
The AD7147A has an SPI-compatible serial interface, and the AD7147A-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 AD7147A is available in a 25-ball, 2.3 mm × 2.1 mm WLCSP and operates from a 2.6 V to 3.6 V supply. The operating current consumption in low power mode is typically 28.96 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
Product Lifecycle Not Recommended for New Designs
This designates products ADI does not recommend broadly for new designs.
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.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.