The DAC is hybrid converters, high MSBs using thermometer, while LSBs using binary code. I have given it enough time to settling down. And I have observed the vdd variation, it will settle in several nano second, and the digital code is about several kilo herz. it is a ideal inductor. In our process, it doesn't afford inductor model.
I have said I have made an experment. Other than the DAC circuit(without inductor), I have put an inductor in the circuit, but it has nothing with DAC.
But the result is uncorrect. So I doubt the reliability of the hspice tool on indcutor.