Sample-and-hold device using complementary bipolar technology

摘要

The proposed sample-and-hold device using a complementary bipolar technology comprises a follower input stage having an input receiving a voltage Vin to be sampled, at least one sampling circuit having a switching stage 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 comprising 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 transistor and its base connected to the emitter of the second transistor. Application to analog-digital converters, analog signal processing systems.