CapTouch™ Programmable Controller for Single-Electrode Capacitance Sensors
The AD7148 CapTouch™ Programmable 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 ultra thin applications.
The AD7148 is an integrated capacitance-to-digital converter (CDC) with on-chip environmental calibration. The CDC has 8 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. The external sensors can be arranged as a series of buttons, as a scroll bar or wheel, or as a combination of sensor types. 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 AD7148 is designed for single electrode capacitance sensors (grounded sensors.) There is an active shield output to minimize noise pick-up in the sensor. For floating, or two electrode sensors, use the AD7143.
The AD7148 has on-chip calibration logic to account for changes in the ambient environment. The calibration sequence is performed automatically and at continuous intervals, while the sensors are not active. This ensures that there are no false or non-registering touches on the external sensors due to a changing environment.
The AD7148 has an I2C-compatible serial interface, as well as interrupt output. There is a VDRIVE pin to set the voltage level for the serial interface independently from VCC.
The AD7148 is available in a 16-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.
- Cell Phones
- Personal Music and Multimedia Players
- Smart Hand-held Devices
- Television, A/V and Remote Controls
- Gaming Consoles
- Digital Still Cameras
This designates products ADI does not recommend broadly for new designs.
Cooking Inductively: ADI iCoupler Technology Isolates the Hob and the User...
By Jerome Patoux, Analog Devices, Inc. (Analog Dialogue, Vol. 42, March 2008)
MS-2210: Designing Power Supplies for High Speed ADC
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.
Didn't find what you were looking for?
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.