A frequency compensated operational amplifier includes: an input stage, for receiving an input signal; an output stage, coupled to the input stage, for generating an output signal according to an output of the input stage; a first current source, for providing a first bias current; a second current source, for providing a second bias current identical to the first bias current; an Ahuja compensation circuit, comprising: a matched transistor pair, coupled to the first current source and the second current source; a capacitor coupled between the matched transistor pair and the output stage; and a transconductance boosting circuit, coupled to the matched transistor pair, for boosting transconductance of the matched transistor pair.