Because the output is from the collectors (or drains as it is here), the miller capacitance makes such a topology quite unstable, especially for MOSFETs which have huge Ciss.

• 由于输出是集电极（这里是源极），米勒电容使得这样的结构很不稳定，尤其这里的MOSFET具有很大的输入电容。