CDC enables touch-control sensitivity in portable electronic devices

Norwood, Mass. — Analog Devices released a capacitance-to-digital converter (CDC) integrated touch controller which allows designers to add responsive user controls, including scroll wheels and touch pads, to portable electronic devices. The AD7147 provides accurate measurement and responsiveness, and features the addition of an active-shield feature for improved noise performance. Requiring only a single PCB (printed-circuit board) for full implementation, the CDC is suitable for ultra-thin mobile electronic devices.

The configurable AD7147 CDC features 13 capacitance inputs and femtofarad resolution, allowing mobile electronics designers to implement a touch pad, scroll wheel, slider, or up to 36 buttons per device. The addition of integrated active-shield technology protects the AD7147 from capacitance-to-ground pickup and other noise sources in the system, allowing designers the freedom to place the sensor away from the main system IC.

The improved response of the analog front-end allows end-users to experience more accurate finger navigation and improved device performance, while continuing to offer designers per-channel sensitivity adjustment for sensor-response fine tuning. The AD7147 includes on-chip sensitivity algorithms which compensate for changes in temperature and humidity, and ensure users with different finger sizes receive the same responsive sensor performance.

The CDC typically consumes 1 mA in full-power mode, 50 µA in low-power mode and a shutdown power consumption at 2 µA. The AD7147 includes an SPI-compatible serial interface, while the AD7147-1 features an I2 C-compatible serial interface.

Availability: Samples available
Pricing: $1.30 each in 1,000-piece quantities
Data Sheet: AD7147 CDC

Analog Devices, 800-262-5643,

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