為什麼這篇MOS varactor鄉民發文收入到精華區：因為在MOS varactor這個討論話題中，有許多相關的文章在討論，這篇最有參考價值！作者elian1 (Baseball在面前)看板comm_and_RF標題[問題]請問varacto...
請問各位前輩
junction varactor和MOS varactor比較的優缺點為何?
我是知道個大概 但由於要寫論文 所以需要詳細的資料
但又不知道這方面的詳細資料要去哪找
還請知道哪裡找的到這些資料的前輩跟我指點一下 感激!!
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◆ From: 140.116.214.108
※ 編輯: elian1 來自: 140.116.214.108 (05/15 21:49)
※ 編輯: elian1 來自: 140.116.214.108 (05/15 21:51)
※ 編輯: elian1 來自: 140.116.214.108 (05/15 22:06)
推 jyhbna:On the use of MOS varactors in RF VCOs Andreani, P. 05/15 23:30
> -------------------------------------------------------------------------- <
作者: deathcustom (沒有目指到@@) 看板: comm_and_RF
標題: Re: [問題]請問varactor的資料
時間: Mon May 15 22:20:07 2006
※ 引述《elian1 (Baseball在面前)》之銘言：
: 請問各位前輩
: junction varactor和MOS varactor比較的優缺點為何?
: 我是知道個大概 但由於要寫論文 所以需要詳細的資料
: 但又不知道這方面的詳細資料要去哪找
: 還請知道哪裡找的到這些資料的前輩跟我指點一下 感激!!
Razavi有一篇講到這個
Devices and Circuits for Phase-Locked Systems
Behzad Razavi
一開始就有
主要是Reverse Bias對 J Varactor的效應
而MOS Varactor對此免疫
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推 elian1:感恩!! 05/16 00:06
> -------------------------------------------------------------------------- <
作者: deathcustom (沒有目指到@@) 看板: comm_and_RF
標題: Re: [問題]請問varactor的資料
時間: Tue May 16 01:02:29 2006
※ 引述《elian1 (Baseball在面前)》之銘言：
: 請問各位前輩
: junction varactor和MOS varactor比較的優缺點為何?
: 我是知道個大概 但由於要寫論文 所以需要詳細的資料
: 但又不知道這方面的詳細資料要去哪找
: 還請知道哪裡找的到這些資料的前輩跟我指點一下 感激!!
As supply voltages scale down, pn junctions become a less
attractive choice for varactors. Specifically, two factors limit
the dynamic range of pn-junction capacitances: (1) the weak
dependence of the capacitance upon the reverse bias voltage,
e.g., Cj = Cj0/(1+Vr/Φb)^m, where m ~ 0.3.; and (2) the
narrow control voltage range if forward-biasing the varactor
must be avoided.
http://www2.ee.ntu.edu.tw/~b1901050/16-05-06_0055.jpg
As an example, consider the LC oscillator shown above.
It is desirable to maximize the voltage swings at nodes X and
design of the stage(s) driven by the VCO. On the other hand,
to avoid forward-biasing the varactors significantly, Vx and
Vy must remain above approximately Vcont - 0.4V. Thus,
the peak-to-peak swing at each node is limited to about 0.8V.
Note that the cathode terminals of the caractors also introduce
substantial n-well capacitance at X and Y, further constraining
the tuning range.
In contrast to pn junctions, MOS varactors are immune to
forward biasing while exhibiting a sharper C-V characteristic
and a wider dynamic range. If configured as a capacitor(as
below), a MOSFET suffers from both a nonmonotonic C-V behavior
and a high channel resistance in the region between accumulation
and strong inversion. To avoid these issues, an "accumulation-mode"
MOS varactor is formd by placing an NMOS device inside an n-well......
http://www2.ee.ntu.edu.tw/~b1901050/16-05-06_0056.jpg
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推 Ccwind:感謝 但近拍技術需要加強 05/16 09:51
推 deathcustom:那是手機拍的，抱歉......>< 05/16 12:17