5.25GHz CMOS 功率放大器設計及單晶Balun之研究

Abstract

中 文 摘 要 近來由於無線通訊的蓬勃發展，加上半導體技術的進步，將整個通訊系統(包括基頻及射頻部分)整合在一個晶片當中已成為一種必然的趨勢。本篇論文當中將介紹以0.25um CMOS mixed mode製程設計5GHz頻段的射頻驅動放大器及功率放大器。 功率放大器及驅動放大器中匹配電路均以螺旋電感及MIM電容等集總元件整合於IC當中，其中功率放大器是操作於Class A的模式，設計時以功率匹配(Power Matching)方式來達到最大功率輸出及效率，而驅動放大器則使用增益匹配(Gain Matching)方式來增加驅動能力及其電路整體增益。功率放大器的量測結果如下和模擬結果相當接近，增益5.66dB，輸出P1dB為13.7dBm(FCC中規範應小於 17dBm)，PAE@P1dB時為13%，IIP3為24dBm，而驅動放大器在5.25GHz的功率增益為5dB，輸出P1dB為6.7dBm。 因為電路操作頻率高於5GHz，設計電路時需要使用較高自振頻率(Self resonate frequency)的被動元件，論文中將討論量測到的螺旋電感testkey的模擬和量測結果，其中包括寬度為7um、10um、15um及雙層電感四種，由量測結果可以得之雙層電感同時具有較高的自振頻率(SRF)及Q值。另外，由於許多RFIC是採用差動式的電路架構，在晶片當中可利用螺旋電感互繞的方式實現Balun(Balance-to-Unbalance)電路，可應用於差動式電路(如LNA)與單端電路間(Antenna)的轉換，由量測結果顯示，雖然這種架構具有接近180相位差(173~183度)，但其最大的缺點是由於矽基板中的損耗造成Balun的耦合度很低(-7dB)。

Abstraction Recently, with the promising developing of wireless communication and the improvement of semi-conductor technology, to integrate all communication system (including base-band and RF) becomes a trend. This thesis will present 5GHz RF Power Amplifier and Driver Amplifier which are designed by 0.25um CMOS mixed mode technology. Matching network of Power Amplifier and Driver Amplifier are integrated in IC by on-chip lump elements, such as Spiral inductor and MIM capacitor. RF Power Amplifier is operated in Class A mode, and is designed with Power Matching to achieve maximum Output Power and Efficiency; Driver Amplifier is designed with Gain Matching to increase Power Handling capability and System Gain. The measured results of Power Amplifier agree with simulative results: Power Gain=5.66dB, Output P1dB=13.76dBm, PAE@P1dB=13%, OIP3=24dBm; Power Gain of Driver Amplifier at 5.25GHz is 5dB, Output P1dB is 6.7dB. To design a RFIC that operating frequency is over 5GHz needs passive component with high self resonate frequency. This thesis will discuss the simulative results and measured results of Spiral inductor testkey, which including three different widths (7um, 10um, 15um respectively) and double-layer inductor. In measured results, double-layer inductor has both high self-resonate-frequency and Q factor. Besides, Balun(Balance-to-Unbalance), which uses as an adaptor between Differential and Single-ended circuit (LNA and Antenna respectively), can be implemented by inter-wound Spiral Inductor. The measured results show that, although this Balun structure has nearly 180 degree phase-difference (173~183 degree), the most disadvantage is the low coupling factor (-7dB) owing to the lossy Si substrate.