开关管长度的设计如何考量？
若用最小长度，我扫一下它的W大概为4u的时候（TSMC-0.13rf），就能有较为理想的开关效果。
那么它的长度选择如何选, 基于工艺偏差取长管?
横轴W，纵轴C，蓝线是Vgs=1.2，红线Vgs=0，mim电容158f。当W大概为4u的时候，开关前后电容达到较大值，再增大W效果增加缓慢
不知道你的应用对漏电敏感么，这个要查一下工艺文档进行计算
能具体一点吗?L 越短不是Vt越大，防漏电性能越好啊
只要vgs足够小，沟道离形成还远着呢，Vt的影响就没这么大。主要漏电是反偏结的漏电，vds大了耗尽区也变大，沟道越短这个耗尽区就离另外一个N+更近，漂过去的电子就越多，甚至还有隧过去的
谢谢，有没有什么仿真方法，可以评估这个漏电性能与L的关系?
如何减小漏电流呢?这个不是和工艺有关系吗?我是用TFT做开关管的，而且管子一般都是4um，如果尺寸不变，是否只能考虑改进工艺了?谢谢
你仿仿试试吧，t13的模型可以的
TFT?不懂那个，但我想就是应该从工艺角度出发，design是没办法的，工艺有招的，这里做深那里做浅或者搞个特殊形状
发现L=0.5u后，漏电流显著下降。
也就是说，开关管的L取0.5u就行了吧
实际VDS有这么大啊，如果走的电流不大的话建议w/l=1/.6就万无一失了
I see little point to optimize the switch size for DCCA in VCO.It looks funny if your purpose is just to have a larger effective C.
Have you checked whether your equation is correct enough to calculate the effective capacitor when using Port(it is frequency related) ?
if you know Ron/Coff of the switch(Q value, tuning range),it is good enough for a DCCA design.
5GHz SP 仿真
把L 调到0.5u后，即使W=5u。
开启后接入的有效电容只有70fF，而MIM电容大小是158fF。假设我希望能接入100fF，我应该调节MIM吗?
the imaginary part of Y11 is not purely capacitance, and it is better for you tomake some derivation on imag(Y11) based on the first order assumption of the switch (on: Ron,Con, off: Roff, Coff). it is very helpful to design a reasonable DCCA in an intuitionalway
70fF is due to the larger Ron, you need to reduce Ron by increase W, usually the Coff is OK to be about 1/10 of Cmim
dibl...
L越大，VT越大吧
It depends, for long channel devices, Vth increases as Leff increases just as the case in Razavi's textbook,
However, in modern process (i.e. 130nm or 65nm), as Leff increases, Vth increases at first and decreases at
a certain Leff point. Very interesting. This is so called RSCE effect
进来学习。
research
抠得这么细致，学习了！
六管开关W/L两三倍，L取最小两倍左右呢，大神
防漏 長通道就是了
如此细致，领教。