为什么ecsm或ccsm比nlm更精确？

NLDM是两维查找表
ECSM or CCSM 是三维查找表

个人认为电流源模型更主要的好处是，它能够解决一些电压源模型力不能及的问题，例如多驱动。
下面是copy来的：
Current-source models are a replacement for the nonlinear delay models used with the ".lib" library format. Those table-lookup models capture single data points for timing and represent drivers as voltage sources. A current-source model, in contrast, contains a current waveform that more closely matches the Spice behavior of a cell.
How they differ
Backers of both CCS and ECSM say the models come to within 2 or 3 percent of Spice accuracy and are well-suited to modeling long interconnects, multiple-voltage domains, nonlinear IR drop, dynamic voltage frequency scaling and the Miller capacitance effect.