A cascode transistor circuit comprising a depletion-mode switch in series with a normally-off switch between a drain output terminal and a source output terminal. The circuit also includes a controller comprising a controller output terminal configured to provide a normally-on control signal for a normally-on control terminal of the depletion-mode switch, wherein the normally-on control signal is independent of the normally-off control signal; a negative voltage source configured to provide a negative voltage to the normally-on control terminal of the depletion-mode switch; and a feedback capacitance between the drain output terminal and a control node in a circuit path between the controller output terminal and the normally-on control terminal of the depletion-mode switch.