非對稱性LDMOSFET-based 射頻收發切換開關電路之設計與分析

Design and Analysis of Asymmetric LDMOSFET-based RF Transmit/Receive Switch Circuit

陳竫瑜(Ching-Yu Chen)

指導教授 ： 龔正 ； 黃智方

國立清華大學/其它/半導體元件及製程產業研發碩士專班/碩士(2010年)

摘要

近年來，由於通訊產品的推陳出新，使得功率元件的需求大幅增加。為了順應電路積體化的潮流，將功率元件與低壓電路整合在同一晶片上，LDMOSFET是平坦化製程的功率元件，主要應用在商業通訊的和射頻電路上，因此在設計高頻積體電路時，一個準確的電晶體模型，能精確的提供電路設計者元件的各種特性，是達成設計電路成功很重要的一環。 本論文利用0.25μm的BCD製程的LDMOSFET，設計出操作在900 MHz之射頻收發切換開關及元件，利用直流高頻量測方法，萃取LDMOSFET電晶體外部寄生元件參數，再經由矩陣轉換求得內部本質元件參數，進而建立功率元件的小訊號等效模型。另外以LDMOSFET 電晶體來設計高功率、低損耗之射頻收發切換開關，使用萃取後的功率元件參數，來建立射頻收發切換開關的等效電路，模擬射頻收發切換開關的工作原理，可看出S參數模擬與量測結果的有一致的表現性。本論文中使用0.25μm的LDMOSFET 製程設計的功率元件，在900MHz時可達到增益為10.2dB和16.7 dBm的P1dB，最大輸出功率可達到28 dBm，射頻收發切換開關在900MHz 可達到29 dBm的P1dB，1.0 dB以下的插入損耗及20 dB的隔離度，線性度 (IIP3) 達25 dBm。

關鍵字

射頻收發切換開關 ； 功率元件

並列摘要

In recent years, following the introducing of state of the communication products, demands for power devices have risen substantially. In keeping with the trend of circuit integration, traditional vertical device needs to be changed to lateral structure to make it possible for the integration of power devices and low voltage circuit on the same chip. LDMOSFET transistor is one of the most important high power devices for commercial communication applications and RF circuit. It is very important to set up an accurately model which contains the high frequency and it is helpful to design a RF circuit composed of these transistors.

This thesis contains both the small-signal modeling methods of RF LDMOSFET device. Utilizing high frequency measurement method, extrinsic parameters of device can be extracted. And then using matrix operation method to obtain intrinsic parameters of the device, and set up the small-signal equivalent model of the transistor and this thesis presents comprehensive methods for the application of RF LDMOSFET Transmit/Receive switch with high power-handling capability and low insertion loss and Utilizing extracted parameters of LDMOSFET device and set up the equivalent model of the RF Switch Circuit. The model simulates the operation modes of RF Switch Circuit. The good agreement between measured and modeled S parameters justifies the accuracy of our equivalent circuit model.

RF power device based on a 0.25μm LDMOSFET process at 900MHz. The measured performance of gain up to 10dB, input 1-dB compression point of 16.7dBm and the power output up to 27dBm can be achieved. The RF switch circuit implemented using 0.25μm LDMOSFET transistors for 900MHz wireless application have been present. In particular, 900MHz switch with the measured insertion loss less than 1 dB, isolation up to 20dB and input third-order intercept point of 25 dBm.

並列關鍵字

RF T/R Switch ； RF Power Device

參考文獻

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