Active-bootstrapped gain-enhancement technique for low-voltage circuits

A gain-enhancement technique based on active bootstrapping is proposed which ideally increases the low-frequency gain by two gain stages with no speed penalty and without adding to the phase shift. Therefore, high-frequency performance and feedback stability are not compromised. In practice, the gain enhancement will be limited by nonidealities. The technique is particularly suited for minimum supply voltages since no cascodes are used and, although the discussion pertains to CMOS, can also be applied in bipolar and BiCMOS technologies. A complete analysis, including the effects of nonidealities, is performed. A generally applicable design methodology is formulated.