A bias device includes a first branch and a second branch. The first branch includes a first bipolar device and a corresponding bias circuit. The second branch includes a second bipolar device and a corresponding bias circuit. A self-bias circuit is connected to the first and second branches. A first current generator injects a first auxiliary current into the first bipolar device. A second current generator injects a second current into the second bipolar device that is equal or proportional to the first auxiliary current. The bias device stabilizes the operating point of a circuit.