ON Semiconductor's IC Simplifies Design and Miniaturises Touch Sensors
ON Semiconductor, a supplier of high performance silicon solutions for energy efficient electronics, has introduced a highly integrated capacitance-to-digital converter IC.
The device will speed the implementation and reduce the component count of electrostatic capacitance touch sensor applications.
The new LC717A00AR, which is the first in a series of ON Semiconductor touch sensor integrated circuits (ICs), simplifies the replacement of mechanical switches with capacitive touch sensors.
Relevant applications include home appliances, audio/visual equipment, computer peripherals and automotive instrument panels.
Featuring eight capacitor sensing inputs and eight digital outputs, the LC717A00AR uses a proprietary differential capacitance detection technology to enable high sensitivity and high noise resistance. A built-in logic circuit detects the ON/OFF state of each input and outputs the appropriate result without the need for any additional components or control software. Capacitances in the femto Farad order can be detected and touch sensitivity is pre-configured, eliminating the need for complicated sensitivity adjustments.
"Because of its high sensitivity, the LC717A00AR is ideal for applications where users may wear gloves or where an air gap or a thick, protective glass cover is needed such as washing machines, refrigerators and cooking appliances," says Takekiyo Okumura, general manager of ON Semiconductor's SANYO division. "In addition to integrated anti-noise circuitry, the device automatically compensates for changes in temperature and humidity to prevent false touch detection and operational failure from environmental changes."
As well as operating as a standalone device, the LC717A00AR allows parameters to be modified using an external microcontroller via a built-in serial interface that can be configured for I2C or SPI operation. The device is compatible with a supply voltage of 2.6 volts (V) to 5.5V and operates with a typical current consumption of 320 micro-amps (µA) at a supply voltage of 2.8 V. Rated operating temperature is -40°C to 105°C.
The LC717A00AR is available in a lead-free VCT28 package and budgetary pricing is $1.50 in quantities of 2,000.
