現今新興的超低功率消耗的應用，像是無線感測系統等，越來越受到大家的關注與重視。為了能夠達到超低功率消耗的需求，以延長產品的使用時間，次臨界電壓數位電路設計便成為一個新興且可行的方法之一。在本篇論文裡，我們使用在基頻處理器中一個重要的運算單元，也就是相關器，作為我們主要的數位電路設計，以表現電路能夠支援大範圍操作電壓調整（從高於臨界電壓區域，乃至於次臨界電壓區域）的可行性。一個出現於次臨界電壓電路設計的重要問題，便是製程變異對電路效能的敏感性與影響大大地增加。為了能夠降低製程變異的影響，我們從電路結構的設計上來解決此問題，取代一般常見會消耗大量面積的基底偏壓技術。為了使得操作於次臨界電壓區域的電路與高於臨界電壓區域的電路能夠正確地溝通，我們便設計了一個新的且能夠有效地轉換次臨界電壓訊號到高於臨界電壓訊號的電壓準位轉換器。在本篇論文中，相關器與電壓準位轉換器皆使用UMC 90nm的製程技術設計電路。根據模擬的結果可知，次臨界電壓相關器電路可正確地操作於200mV的供應電壓，並且提供40MHz的效能，同時僅消耗22uW的功率。然而，此相關器不但可以操作在200mV到1V的供應電壓範圍，還能夠在供應電壓為1V時，提升效能達到800MHz，同時消耗5.7mW的功率。

The emerging applications such as wireless sensor networks demanding for ultra low power consumption to prolong operating time without changing batteries are getting more and more attentions. Digital sub-threshold circuit design has become a viable method to achieve ultra low power consumption requirements. In this thesis, the correlator, one major component of the baseband receiver, is used to demonstrate the feasibility of operating at sub-threshold to super-threshold supply range. The increasing sensitivities of the process variations at sub-threshold region are minimized using circuit structures instead of body biasing which consumes large area overhead. A novel level converter that can efficiently convert the sub-threshold input signals to super-threshold signals is also proposed and integrated with the sub-threshold correlator. The correlator implemented using 90nm technology can operate at 200mV with 40MHz and consumes only 22 W. The correlator not only can operate with supply voltage from 0.2V to 1V, but also can scale up the performance to 800MHz at 1V and consumes 5.7mW.

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