美国Semtech上市了号称业界最小功耗的静电容量式接触传感器控制IC(英文发布资料)。有支援12个静电容量式接触传感器的12通道品“SX8643/44/45”和支持8个传感器的8通道品“SX8646/47/48/49”。该公司称,采用这些IC,即可令配备静电容量式接触传感器的按钮、滑触头、触摸轮(Touch Wheel)等得以实现。具体的用途包括手机、可擕式媒体播放器以及笔记本电脑等。
两种IC均在输入部分集成了分解能10bit的A-D转换器。由于分解能高,因此可进行高精度的静电容量检测。具体而言,即使遮盖了最厚5mm的被覆材料,也能检测出静电容量。外置的静电容量式接触传感器可直接接入各输入端子。无需电阻以及电容器之类的外置部件。此外,还集成了8个可用于LED驱动的通用输入输出(GPIO)埠。使用PWM信号,可进行256灰阶的线性调光、或者对数调光。
12通道品的消耗电流,扫描时间为30ms的主动模式时为标准220μA,扫描时间为195ms的Doze模式时为标准80μA,休眠模式时为标准8μA。8通道品的消耗电流,扫描时间为30ms的主动模式时为标准175μA,扫描时间为195ms的Doze模式时为标准80μA,休眠模式时为标准8μA。
两种型号均具备时钟频率为400kHz的I2C接口。工作温度范围为-40~+85℃。12通道品的封装采用面积为5mm×5mm的32端子QFN,8通道品采用面积为4mm×4mm的28端子QFN封装。
产品特性
A fully integrated capacitive sensing solution capable of
resolving 12 inputs with up to 100pF of offset capacitance at
full sensitivity
• Supported Application:
– Button, Slider, Scrollwheel
• 8 LED Drivers with Individual 256-step PWM control
– Autolightening, intensity/breathing control for various ligihting effect
• Configurable Auto-Offset Compensation
– Upon Power Up
– User-defined Intervals (i.e. cycle, trigger levels)
• On-chip 10-bit ADC provides Superior Sensitivity
– Able to sense small cap. changes down to 100fF
• Programmable Scan Time w/ Low Power Consumption
– Fast Mode (30ms): ~260uA
– Doze Mode (195ms): ~80uA
– Sleep Mode: ~8uA
• Built-in MTP for Parameters Customization & Field Programmability
– Gain, Threshold, Scan Time, LED/Button Mapping, etc
• Fast /INT Response time
• No External Components per Sensor
• Smart Sleep Mode Sequence to Wake up
• 400kHz I2C Interface with Programmable Slave Address
• 3kV HBM ESD Protection
• Ultra Small Footprint: 32-Pin (5x5mm) QFN
• -40°C to +85°C Operation
产品应用
• Notebook/Netbook/Portable/Handheld computers
• Cell phones, PDAs
• Consumer Products, Instrumentation, Automotive
• Mechanical Button Replacement
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