適用於LTE並具有可調增益的寬頻BALUN低雜訊放大器

A WIDEBAND BALUN-LNA WITH GAIN CONTROL FOR LTE

何宗勳(Tsung-Hsun Ho)

指導教授 ： 黃淑絹

大同大學/電機資訊學院/通訊工程研究所/碩士(2012年)

摘要

本論文介紹一個適用於LTE (700MHz - 2.7GHz)並具有可調增益功能的寬頻BALUN低雜訊放大器。此電路架構使用兩組放大器串接而成並且含有高低增益兩種模式，另外為了縮小佈局面積，因此不選用電感元件。在第一級放大器中，採用共閘極-共源極放大器所組成的平衡不平衡轉換(Balanced-to-Unbalanced converter, BALUN)電路做為基礎，搭配一對疊接於此的共閘極放大器配合電容交互耦合(Capacitor Cross-Coupling, CCC)技巧所構成；此架構可免除天線末端額外採用一轉換電路做連接，便於輸入阻抗的匹配，並利用輸出為差動形式及電容交互耦合技巧去消除雜訊。第二級放大器則採用一個具有可調增益功能的差動放大器，以達到動態範圍的接收。
模擬上，使用台積電0.18μm mixed signal 1P6M CMOS製程搭配Aglient ADS軟體去模擬S參數、穩定度、線性度以及雜訊度。本電路於高增益模式的模擬下，放大增益最高可達17.76 dB，雜訊度最低為2.98 dB，輸入第三階截止點可保持-12.5 dBm以上。於低增益模式的模擬下，放大增益最高可達11.28 dB，雜訊度保持於3.9 dB內，輸入第三階截止點則可維持-12.5 dBm以上。整個電路的佈局面積為0.42 mm2。

關鍵字

低雜訊放大器 ； 長期演進 ； 雜訊消除

並列摘要

In this thesis, a wideband BALUN-LNA for LTE (700MHz to 2.7GHz) applications is presented. The LNA architecture is composed by two amplifier stages and has two operation modes, low-gain and high-gain modes. In addition, this LNA does not use inductors in order to reduce the layout area. In the first stage, the circuit is based on the BALUN which combined CG with CS amplifiers; in addition a pair of CG amplifiers is cascoded on it which employs the capacitor cross-coupling technique for noise cancellation. This architecture does not need the conversion circuit which connected to an antenna and is convenient to input matching. The second stage uses the differential amplifier with gain control function to achieve the receiving of dynamic range.
The LNA is implemented in TSMC 0.18 μm 1P6M CMOS process. We use Aglient ADS to simulate the S parameters, stability and linearity. In the high gain mode, the maximum gain is 17.76 dB, the minimum noise figure is 2.98 dB and the IIP3 value is kept above -12.5 dBm. In the low gain mode, the maximum gain is 11.28 dB, the noise figure is kept under 3.9 dB and the IIP3 value is kept above -12.5 dBm. Finally, we use LAKER L3 to implement IC layout and the total chip area is 0.42 mm2.

並列關鍵字

LNA ； Noise canceling ； LTE

參考文獻

[2] B. Razavi, Design of Analog CMOS Integrated Circuits. McGraw-Hill, 2001.

[3] B. Razavi, RF Microelectronics. Prentice-Hill, 1998.

[5] International Telecommunication Union, http://www.tu.int/ITU-R/

[6] 3rd Generation Partnership Project, http://www.itu.int/net/pressoffice/press_releases/2010/40.aspx.

[7] 3rd Generation Partnership Project, http://www.3gpp.org/LTE.