美國(guó)Semtech上市了號(hào)稱(chēng)業(yè)界最小功耗的靜電容量式接觸傳感器控制IC(英文發(fā)布資料)。有支援12個(gè)靜電容量式接觸傳感器的12通道品“SX8643/44/45”和支持8個(gè)傳感器的8通道品“SX8646/47/48/49”。該公司稱(chēng)，采用這些IC，即可令配備靜電容量式接觸傳感器的按鈕、滑觸頭、觸摸輪(Touch Wheel)等得以實(shí)現(xiàn)。具體的用途包括手機(jī)、可擕式媒體播放器以及筆記本電腦等。

兩種IC均在輸入部分集成了分解能10bit的A-D轉(zhuǎn)換器。由于分解能高，因此可進(jìn)行高精度的靜電容量檢測(cè)。具體而言，即使遮蓋了最厚5mm的被覆材料，也能檢測(cè)出靜電容量。外置的靜電容量式接觸傳感器可直接接入各輸入端子。無(wú)需電阻以及電容器之類(lèi)的外置部件。此外，還集成了8個(gè)可用于LED驅(qū)動(dòng)的通用輸入輸出(GPIO)埠。使用PWM信號(hào)，可進(jìn)行256灰階的線(xiàn)性調(diào)光、或者對(duì)數(shù)調(diào)光。

12通道品的消耗電流，掃描時(shí)間為30ms的主動(dòng)模式時(shí)為標(biāo)準(zhǔn)220μA，掃描時(shí)間為195ms的Doze模式時(shí)為標(biāo)準(zhǔn)80μA，休眠模式時(shí)為標(biāo)準(zhǔn)8μA。8通道品的消耗電流，掃描時(shí)間為30ms的主動(dòng)模式時(shí)為標(biāo)準(zhǔn)175μA，掃描時(shí)間為195ms的Doze模式時(shí)為標(biāo)準(zhǔn)80μA，休眠模式時(shí)為標(biāo)準(zhǔn)8μA。

兩種型號(hào)均具備時(shí)鐘頻率為400kHz的I2C接口。工作溫度范圍為-40～+85℃。12通道品的封裝采用面積為5mm×5mm的32端子QFN，8通道品采用面積為4mm×4mm的28端子QFN封裝。

產(chǎn)品規(guī)格

產(chǎn)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

產(chǎn)品應(yīng)用
• Notebook/Netbook/Portable/Handheld computers
• Cell phones, PDAs
• Consumer Products, Instrumentation, Automotive
• Mechanical Button Replacement