Capacitive Controller ICs Capacitive Switch Controller ICs BU21079F General Description Key Specifications BU21079F is a capacitive switch controller used for Input voltage range 3.0V to 5.5V operating switches. Operating temperature range -25 to 85 Low power consumption is achieved using the Operating current 2.5mA (Typ) intermittent operation mode. Detect cycle 6msec (Typ) In addition to a regular simple switch, it supports matrix switches which are arranged in the matrix sensors. If Packages external noise and temperature drift are detected, the BU21079F : automatic self-calibration is activated. Features 8 capacitive sensor ports Supports matrix switches. Maximum of 16 switches. Automatic self-calibration Continued touch detection Sends an interrupt when there is a detected result of switch operation 2-wire serial bus interface 3.3V or 5.0V single power supply SOP16 Built-in Power-On-Reset and Oscillator 10.006.201.71 Applications Electronic devices with multiple switches. Information appliances such as printers. AV appliances such as digital TV and HDD recorder. Notebook PC. Air-conditioner. Refrigerator. Electrical rice cooker. Typical Application Circuit Figure 1. Typical Application Circuit Product structureSilicon monolithic integrated circuit This product has no designed protection against radioactive rays www.rohm.com TSZ02201-0Y1Y0FZ00150-1-2 2013 ROHM Co., Ltd. All rights reserved. 1/34 2013.09.25 Rev.001 TSZ2211114001 4.7k 4.7kDatasheetDatasheet BU21079F OVERVIEW BU21079F is a capacitive sensor controller for switch operation. BU21079F has the following blocks: AFE (Analog Front End) detecting capacitance, A/D converter, MPU, 2-wire serial bus interface compatible with I2C protocol, power-on-reset, and oscillator. It is operated with a 3.0V to 5.5V single power supply. The results detected during switch operations (Touch/Release/Hold) are stored in a register. An interrupt is sent from INT port to the host when a register is updated during operations. If external noise and temperature drift are detected, automatic self-calibration is activated. When continuous monitoring of the host is unnecessary, the load of the host will be reduced. Intermittent operation When touch ON is detected, its operation shifts from intermittent operation to normal operation. When touch OFF is detected, its operation shifts from normal operation to intermittent operation, and the operating power is decreased. Sensing during intermittent operation is called check sensing and sensing during normal operation is called normal sensing. Simple switch One sensor is assigned to one switch. Each simple switch has the registers for the detected Touch/Release/Hold operations. Simple switches support multi-detect Touch/Release/Hold. It is possible to mask unused switches. Matrix switches The cross points of the sensors which are arranged in a matrix can be assigned to individual switches. Each matrix switch has registers for detected Touch/Release/Hold operations. Matrix switches do not support multi-detect Touch/Release/Hold. It is possible to mask unused matrix switches. BU21079F supports 16 matrix switches configured by 4x4 sensors. Automatic self-calibration BU21079F checks the status of the sensors based on the detected result. If external noise and temperature drift are detected, the automatic self-calibration is activated in order to get stable detection. Host interface BU21079F is slave device for the host device. 2-wire serial bus is compatible with I2C protocol. Slave Address Is 0x5C. Pin Configurations Figure 2. Pin configuration of BU21079F www.rohm.com TSZ02201-0Y1Y0FZ00150-1-2 2013 ROHM Co., Ltd. All rights reserved. 2/34 2013.09.25 Rev.001 TSZ2211115001