The IT7250 is one 25-channel capacitance sensor detection controller companioned with one ITO film screen module to implement multi-touch functionality. It integrates one single electrode 25-channel capacitance-to-digital converter (CDC), 16-bit high performance RISC CPU, flexible memory support, and many powerful hardware functions. The internal CDC has one automatic calibrate and compensates engine to remove environmental change effect. It also includes one self-learning circuit that can modify the threshold and sensitivity levels automatically to eliminate the impact of different finger sizes to optimize the finger touch detection. The chip includes one 16-bit RISC CPU to calculate the location of the finger touch and handle all data translation. It also includes one 16-bit MAC and one 32-bit divider hardware accelerators to speed up the location calculation. The IT7250 supports one interrupt output that can be used to indicate the finger location has been changed or some user defined actions. The chip supports many flexible internal memory sizes and types, storing the user program and special data to extend special functions so as to meet users’ specific requirements. This chip can reduce the system cost by one supported internal power-on reset generator and one calibrated oscillator, generates 1 MHz, 6 MHz, and 24 MHz clocks.
The IT7250 can support three serial interface types, I2C, SPI, and low-speed USB. The serial interface is to communicate with the host. In addition, I2C interface also supports two address selection pins to specify the device ID address. Through these interfaces, the host can program the internal control registers to configure and control the chip to meet the users’ specific requirements. Besides, they can help communicate the finger locations and some user specified commands.
The IT7250 is available in 40-pad QFN package and operates at 2.6 V-3.6 V power supply only.