Patent ID: 7656199

Claim:
A comparator having first and second inputs, the comparator comprising: a first-stage amplifier having a pair of first differential outputs, and a pair of first differential inputs coupled to the first and second inputs of the comparator, wherein the first-stage amplifier has a low input impedance, wherein the first-stage amplifier comprises a first pair of transistor devices having a first common gate node and forming a differential input stage, wherein the pair of first differential inputs are formed by respective source terminals of the first pair of transistor devices, wherein the first pair of transistor devices are diode-connected transistors; and a second-stage amplifier having a pair of second differential inputs coupled to the pair of first differential outputs of the first-stage amplifier, wherein the second-stage amplifier is operable to generate a single-ended output, and has a higher gain then the first-stage amplifier; wherein the single-ended output of the second-stage amplifier is used to produce an output of the comparator.