Programmable Controller for Capacitance Touch Sensors
The AD7143 is an integrated capacitance-to-digital converter (CDC) with on-chip environmental calibration for use in systems requiring a novel user input method. The AD7143 interfaces to external capacitance sensors implementing functions, such as capacitive buttons, scroll bars, and scroll wheels.
The CDC has eight inputs channeled through a switch matrix to a 16-bit, 250 kHz sigma-delta (Σ-Δ) capacitance-to-digital 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 software to run on the host processor.
The AD7143 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 touched. This ensures that there are no false or nonregistering touches on the external sensors due to a changing environment.
The AD7143 has an I2C-compatible serial interface and a separate VDRIVE pin for I2 serial interface operating voltages between 1.65 V and 3.6 V.
The AD7143 is available in a 16-lead, 4 mm x 4 mm LFCSP-VQ and operates from a 2.6 V to 3.6 V supply. The operating current consumption is less than 1 mA, falling to 50 μA in low power mode (conversion interval of 400 ms).
- Personal music and multimedia playersCell phones
- Digital still cameras
- Smart hand-held devices
- Television, A/V, and remote controls
- Gaming consoles
All products in this family will be obsolete soon. Please contact ADI Sales or Distributors to arrange for final purchases and read our Obsolescence Information to review the time periods for placing final orders and receiving final shipments.
Designing Power Supplies for High Speed ADC
Rarely Asked Questions
Capacitive Sensors: Rugged Enough for the Real World?
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.
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.