A method and apparatus is disclosed for improving high frequency performance
of
an amplifier, such as for example, a current mirror. In one embodiment, a delay
element is introduced in a current mirror signal path to account for signal propagation
delay that may exist in one or more alternative signal paths. The delay element
maintains desired phase alignment at a cascade node of the current mirror thereby
establishing, in one embodiment, the cascode node (Vc) in an AC ground
state. To extend current mirror high frequency capability an embodiment is disclosed
having cross-coupled capacitors, active elements, or one or more other devices
configured to provide positive feedback to one or more current mirror inputs. The
positive feedback may be selectively configured to increase the operational bandwidth
of the current mirror.
