LVT, RVT(SVT, NVT), HVT 的区别

这几个都是CMOS集成电路的Vth阈值电压相关的基本概念。通常将传输特性曲线中输出电压随输入电压改变而急剧变化转折区的中点对应的输入电压称为阈值电压。

HVT = High V threshold. Can be used in the path where timing is not critical. So by using HVT cells we can save power.

LVT - Low V threshold. One should use these cells in timing critical paths. These cells are fast but , comsumes more power due to its leakage. So it will consume more power. So use only when timing is critical.

SVT- Standard V threshold. Best of both world. Medium delay and medium power requirment. So if timing is not met by small magin with HVT, you should try with SVT. And at last LVT.

RVT- Regular V threshold. Another name for SVT.

NVT- Normal V threshold.Another name for SVT.

阈值电压越低，饱和电流越小，速度性能越高；但由于漏电流越大，功耗越差。

速度按快到慢依次排列SLVT, LVT, RVT, HVT。 功耗正好相反。也就是说，HVT的cell阈值电压最大，掺杂浓度越高，泄漏功耗最小；

对于NPN晶体管为n型半导体，电子导电，P衬底多子是空穴，电子越高，导电越困难，阈值电压升高，泄漏功耗降低。 对于PNP晶体管为P型半导体，导电为空穴，N衬底是电子的，混合越高，空穴越少，导电越困难。