The present disclosure describes aspects of a fast settling peak detector. In some aspects, a peak detector circuit includes a first transistor having a gate coupled to an input of the circuit at which a signal is received and a drain coupled to a source of a second transistor. Current may flow in the first and second transistors responsive to the signal. The circuit also includes a third transistor having a gate coupled, via a signal-inverting component, to the input of the circuit and a drain coupled to a source of a fourth transistor. Through an inversion of the signal, other current flowing in the third and fourth transistor can reduce or cancel a frequency component of the current in the first and second transistors. In some cases, this precludes a need to filter the frequency component from an output of the circuit.