射頻互補式金氧半導體低雜訊放大器之靜電放電防護設計

Abstract

本篇論文主旨在設計一個具高靜電放電防護能力之射頻互補式金氧半導體低雜訊放大器。我們提出了一個新形態利用電感電容共振產生阻抗隔絕效果的完整靜電放電防護電路，其中包含了VDD至VSS間的靜電放電防護電路。 論文中第二部份針對靜電放電防護電路的寄生效應對低雜訊放大器特性的影響加以探討，包含S-參數，輸入組抗匹配之變動，並提出一完整之雜訊計算公式，且提供了部分參數分析圖示及電路模擬結果。 第三部分我們設計並實現了一組操作在5.2GHz頻段之互補式射頻金氧半導體低雜訊放大器，分成利用傳統二極體保護及新型態電感電容共振保護與無靜電放電保護之電路三種型態做比較，並實現於一個具厚上層金屬線之標準0.25微米1P5M之互補式金氧半導體製程，其中包括電感模型之建立。 實驗結果顯示具靜電放電防護電路之低雜訊放大器會有中心操作位移之情形，利用一外加的輸出阻抗匹配電路可使之拉回到所設計的頻段。藉使用量測到之S-參數重新模擬的結果顯示，新型態電感電容共振保護之低雜訊放大器與傳統二極體保護比較具有較佳的射頻特性。而實驗結果也顯示新型電感電容共振保護之低雜訊放大器有較低之雜訊指數，因此在未來射頻操作頻率愈加增高的趨勢之下，此設計將成為更適合高頻應用之靜電放電防護電路。 經量測，具新型電感電容共振保護之低雜訊放大器可承受4.9仟伏特之人體靜電放電模式測試及275伏特機器靜電放電模式測試。

A CMOS RF LNA with high ESD sustain ability is presented in this thesis. A novel LC tank ESD protected LNA based on impedance isolation is proposed. The whole ESD design includes power rail ESD clamp circuit between VDD to VSS. In the second part, a detailed and comprehensive noise analysis of the LNA without and with input ESD protection has been investigated, including modified power gain by ESD devices, input matching property, noise figure and the portion of the noise power generated by ESD devices. We provide some noise equation and simulation results in this section. In the third part, three types of 5.2GHz CMOS RF LNA are designed and implement in 0.25-μm CMOS process, including pure LNA without any ESD protection, LNA with novel LC tank ESD protection and LNA with conventional diode ESD protection. We also develop some on-chip inductor modeling. The experimental results show that the center frequencies of ESD protected LNA are shifting. After adding proper output matching network, the ESD protected LNA will have the same center frequency. Re-simulation results based on measured S-parameter show that LC tank protected LNA has better RF performance than diode protected one. And measured noise figure also shows that LC tank protected LNA has lower noise level than diode protected one. Thus the ESD protection with LC tank is more suitable for RF application of higher operating frequency in the future. The LC tank ESD protected LNA can pass a HBM ESD level of 4.9kV and a MM ESD level of 275V.