An operational amplifying circuit are provided. The operational amplifying circuit includes a control circuit, pull-up and pull-down transistors, first and second bias circuits, and a bias voltage generating circuit. The control circuit includes first and second input terminals, and is configured to change, when an input voltage transitions to a first level, a voltage level of a pull-up node and a pull-down node to a second level different from the first level. The pull-up transistor provides a power supply voltage to the output terminal. The pull-down transistor connects the output terminal to a ground voltage. The first bias circuit provides a first bias current to the control circuit. The bias voltage generating circuit generates a bias voltage when the voltage level of at least one of the pull-up and pull-down nodes reaches a threshold voltage level, and the second bias circuit provides a second bias current to the control circuit.

A low noise amplifier and a chip. The amplifier includes a biasing circuit unit, a first amplifying circuit unit, a first adjusting unit, a first signal input, a second signal input and a first signal output; the biasing circuit unit includes a first voltage output and a second voltage output; the first amplifying circuit unit includes a first N-type transistor, a first P-type transistor, a first output capacitor, a second output capacitor, a first impedance and a second impedance; gates of first N-type and P-type transistors are connected to first voltage output and first signal input, and second voltage output and first signal input, respectively, via adjusting unit; source of first N-type transistor is connected to source of first P-type transistor and second signal input; drains of first N-type and P-type transistors are connected respectively to impedance, and to first signal output and second signal output via output capacitor.

Disclosed is a cascode configuration that moves the gate of the cascode substantially without delay relative to an output node by capacitively coupling the latter onto the cascode gates. The passive coupling eliminates the need for actively driving the gates of the cascode. In some embodiments, the only circuitry needed on the cascode gate may be a biasing circuit that limits the swing on the cascode gate between V.sub.max and 2V.sub.max, where V.sub.max is a transistor device rating.