讓我們面對這個一現(xiàn)實：大多數(shù)時候我們的移動設備都是閑置的。無論你多么沉迷于在移動設備上檢查消息、瀏覽網(wǎng)絡、聽音樂還是玩游戲，它大部份的時間都還是 等著你去啟動。然而，在這一段閑置期間，你的設備其實并未完全關閉。例如，如果藍牙功能開啟，它每隔幾秒鐘就必須喚醒，以確定是否有配對設備想傳輸數(shù)據(jù)。 同樣地，它還必須定期檢查按鈕的點選、無線網(wǎng)絡活動，以及進行電池監(jiān)控功能。 根據(jù)SiTime公司表示，其全新的高精度實時頻率(RTC)可在這些作業(yè)期間節(jié)省50%或更多的電源，并使電池的使用壽命增加至少一倍。

SiTimes高精確TCXO為傳感器、藍牙與Wi-Fi等實現(xiàn)更小取樣窗口，從而有助于延長可穿戴式設備的電池壽命。
Source：SiTime公司w5nesmc

SiTime公司執(zhí)行副總裁Piyush Sevalia表示，“透過采用全新的 SiT1552 MEMS 32kHz TCXO (溫度補償振蕩器)實時頻率，對于內(nèi)建大電池的設備而言，所節(jié)省的功率或許不算太多，但對于搭載小型電池的物聯(lián)網(wǎng)(IoT)和可穿戴式設備來說，卻可大幅擴展使用壽命?！? 每 一款移動設備都有一個32kHz的 RTC 來記錄時間，告訴該設備何時該喚醒以及何時履行其職責。大多數(shù)的 RTC 都具有100-250PPM的精確度，這已足以使該設備免于反應遲滯或延遲了。然而，對于像藍牙配件等實時設備，即使是達到20PPM都意味著該軟件設計 者必須包括緩沖時間，才能確保外部設備在數(shù)據(jù)傳送以前正確連接。 基本上，這表示軟件設計者在喚醒作業(yè)開始時增加更多時間，以 確保兩個設備之間的通訊順利進行，然后在作業(yè)結(jié)束設備回到閑置模式以前增加更多時間，以確保所有的資都完成傳輸作業(yè)。然而，透過 SiTimes SiT1552 TCXO RTC ，其準確度達業(yè)界最低的5PPM，可讓軟件編寫人員大幅縮短緩沖時間，從而節(jié)省功率以及延長電池壽命，特別是可穿戴設備。 “當我們開始與客戶討論我們的實時頻率TCXO版本時，并沒意識到這個問題，但他們立即告訴我們一款高精度的 RTC 能夠多么顯著地延長電池壽命——尤其是可穿戴設備，”Sevalia表示。

SiTimes以溫度控制的MEMS振蕩器(TCXO)采用獨特的3D芯片堆棧，其125微米厚的微型MEMS芯片以覆晶安裝在內(nèi)含電子組件的ASIC底部焊點之間。
Source：SiTime公司w5nesmc

該SiT1552 TCXO 采用與其于去年發(fā)表的 SiT15xx (20-100PPM)所用的相同 TempFlat 技術。透過增加芯片上溫度傳感器以及一款“模擬溫度—數(shù)字轉(zhuǎn)換器”(ADC)，SiTime能夠提高精確度至±5PPM。該 SiT1552 TCXO 采用1.5×0.8×0.55mm的芯片級封裝(CSP)，大約是石英晶體的六分之一大小，據(jù)稱是目前最小的實時頻率，且其功耗還不到1微安(uA)。該 MEMS 芯片即小且薄(厚度僅400×400×125微米)，使其適于內(nèi)含電子組件的ASIC底部焊球之間。 該 SiT1552 也瞄準需要長期精確度的設備制造商，例如智能儀表領域等設備需要保持20年或以上的精確度。該組件具有500億小時的使用壽命以及涵蓋 SiTime 的終身保固。 SiT1552 現(xiàn)已量產(chǎn)。從SiTime于2005年成立以來，至今已出貨2.2億顆頻率芯片。 本文授權(quán)編譯自EE Times，版權(quán)所有，謝絕轉(zhuǎn)載 編譯：Susan Hong 參考英文原文：MEMS Clock Cuts Wearable Power in Half，by R. Colin Johnson

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{pagination} MEMS Clock Cuts Wearable Power in Half R. Colin Johnson PORTLAND, Ore. — Let's face it: Most of the time our mobile devices are idle. No matter how addicted you've become to checking for messages, surfing the web, listening to music, or playing games, most of the time it's waiting for you to activate it. However, during this idle time your unit is not totally off. If Bluetooth is turned on, for instance, it has to wake up every few seconds to make sure no paired device is wishing to transfer data. Likewise, it has to periodically check for button clicks, WiFi activity, and for battery supervision functions. During those operations SiTime Corp. of Sunnyvale, Calif., claims its new, high-precision, real-time clock can save 50 percent or more of the power usually expended during idle time, at least doubling the battery life during those periods. SiTimes super-accurate temperature compensated MEMS oscillator (TCXO) helps extend battery life of wearables by allowing smaller sampling windows for sensors, Bluetooth, WiFi, et. al. (Source: SiTime) Sponsor video, mouseover for sound "These power savings might not amount to much for a device with a big battery, but for Internet of Things and wearable devices with tiny batteries, their lifetime can be significantly extended with our new SiT1552 MEMS 32 kHz TCXO [Temperature Compensated Oscillator] real-time clock," Piyush Sevalia, executive vice president of marketing, told EE Times. Every mobile device has a 32 kHz real-time clock to keep track of time, telling its device when to wake up and perform its duties. Most of these real-time clocks have a precision of 100 to 250 parts per million (PPM), which is adequate to keep a device from seeming unresponsive or sluggish. However, for real-time devices like Bluetooth accessories, even 20 PPM means that the software designers have to include buffer time to make sure the external device is connected properly before data is transferred. In essence, this means the software designers add extra time at the beginning of a wakeup operation to make sure both devices are communicating, then more extra time at the end of an operation before the device is put back in idle mode to make sure all the data was transferred. However, with SiTimes SiT1552 TCXO real-time clock, its accuracy is within 5 PPM -- the lowest in the industry -- permitting the software writers to drastically cut down those buffer periods, thus saving power and extending battery life, especially for wearables. "We weren't aware of this as a problem when we started talking to our customers about a TCXO version of our real-time clock, but they immediately told us about how a high-precision, real-time clock could significantly extend battery life -- especially on wearables," Sevalia told us. SiTimes temperature controlled MEMS oscillator (TCXO) uses a unique 3-D chip stack with the tiny 125 micron thick MEMS die flipped and mounted between the solder bumps on the bottom of the application specific integrated circuit (ASIC) containing the electronics. (Source: SiTime) The SiT1552 TCXO uses the same TempFlat technology used in its SiT15xx -- a 20 to 100 PPM part announced last year. By adding on-chip temperature sensor and an analog temperature-to-digital converter (ADC) SiTime was able to increase precision to plus or minus 5 PPM. The SiT1552 TCXO real-time clock also claims the smallest footprint of any TCXO today, a 1.5 x 0.8 x 0.55 millimeter chip scale package (CSP), one sixth the size of quartz crystals. And it consumes less than one microAmp of power. The MEMS chip is so small and thin -- 400 x 400 x 125 microns -- that it fits between the solder balls on the bottom of the application-specific integrated circuit (ASIC) containing the electronics. The SiT1552 is also marketed to device makers that need accuracy over long periods, such as smart meters, which need to stay accurate for 20 years or more. The device has a lifetime of 500 million hours and is covered by SiTime's lifetime replacement warranty, as are all its timing chips. The SiT1552 is in mass production now, and so far SiTime has shipped 220 million total timing chips since its founding in 2005.