Sample-and-hold device using complementary bipolar technology

A sample-and-hold device comprising a follower input stage having one input receiving a voltage Vin to be sampled and at least one output, at least one sampling circuit having a switching stage, the switching stage having at least one control input, one signal input connected to the output of the follower input stage, and one output, the switching stage being controlled by its control input by a digital command to be placed either in a first state called a “follower” state where its output follows the potential at its signal input or in a second state called an “isolated” state where its output is isolated from it signal input, the output of the switching stage being connected to the base of a first follower transistor whose emitter is connected to a terminal of an output sampling capacitor, the sampling circuit furthermore comprises a second transistor, having its emitter supplied by a current source and having its base connected to a potential copying that of the terminal of the output sampling capacitor, and a third transistor controlled by the digital command so as to be crossed by a current when the switching stage is in the “isolated state ”, and so as to be off when the switching stage is in the <<follower>> state, the third transistor having its emitter connected to the base of the first follower transistor and its base connected to the emitter of the second transistor.