High gain, high speed comparator operable at low current

摘要

A comparator includes a differential pair of transistors providing a first amplification stage and receiving inverting and non-inverting input signals. An output transistor is coupled to the differential pair of transistors providing a second amplification stage and transitioning the output signal state when the non-inverting input signal is larger than the inverting input signal. The output node of one of the differential pair of transistors is connected to an input node of a current-tail transistor. The output node of the other differential transistor is connected to an input node of the output transistor. The other nodes of the differential pair of transistors are connected to each other and are coupled to an output node of the current-tail transistor. The output nodes of the differential pair of transistors and an output node of the output transistor are each coupled to a separate current generator that may include a complex impedance element.