Abstract: A circuit protects against electrostatic discharge and includes a pad which receives an external signal source. The transistor of the present invention is connected to the circuit to be protected and includes a semiconductor body of a first conductivity type and serves as the collector of the transistor and is connected to the pad. A first doped region of a second conductivity type is contained in the semiconductor body and serves as the base of the transistor and forms a collector-to-base junction surface with the semiconductor body. A second doped region of the first conductivity type is contained in the first doped region and serves as the emitter of the transistor and forms a base-to-emitter junction surface with the first doped region. The first and second doped regions are electrically connected for establishing a shorted connection between the base and emitter.

Abstract: An electrostatic discharge protection circuit for integration into an integrated circuit device. The protection circuit includes at least one transistor having a first terminal connected to an input or output terminal of the integrated circuit device, a second terminal connected to a supply line for the integrated circuit device, and a control terminal connected to ground. In a preferred embodiment, the transistor is formed by a structure that includes a substrate of a first conductivity type, a first region of a second conductivity type, a second region of the first conductivity type, a third region of the first conductivity type, and a fourth region of the second conductivity type. The third region has greater conductivity than the substrate and the fourth region has greater conductivity than the first region.

Abstract: A protection circuit for a power supply line in a semiconductor device, comprising first and second field-effect transistors, both transistors having their respective drain terminals connected to the power supply line. The gate source terminals of the first transistor are connected to ground through first and second resistors, respectively. The gate and source terminals of the second transistor are connected to the source terminal of the first transistor and to ground, respectively.

Abstract: A protection circuit for a pulse type power supply line of an integrated circuit device. The protection circuit includes a switching circuit having a preset delay, and a first transistor that is connected between the pulse power supply line and ground. The gate terminal of the first transistor is coupled to ground through a first resistor, and to a second power supply line for a low DC voltage through the switching circuit. In a preferred embodiment, the switching circuit includes a second transistor that is connected between the gate terminal of the first transistor and ground. The gate terminal of the second transistor is coupled to the second power supply line through a current generator, and is also coupled to ground through a resistive element and a capacitive element that are connected in parallel.

Abstract: A circuit protects against electrostatic discharge and includes a transistor connected to the circuit to be protected. A semiconductor body of a first conductivity type serves as the collector. A first doped region of a second conductivity type is contained in the semiconductor body and serves as the base. A second doped region of the first conductivity type is contained in the first doped region and serves as the emitter. The first doped region includes a generally H-shaped doped region and a generally ring-shaped doped region forming an opening in which the second doped region serving as the emitter is received. The H-shaped doped region has a deeper junction surface than the junction surface of the ring-shaped doped region, and a dopant concentration that is less than the dopant concentration of the ring-shaped doped region. The H-shaped doped region achieves a low collector-to-base breakdown voltage and the ring-shaped doped region achieves a low snap-back voltage.

Abstract: Device for limiting the working voltage for mechanical switches in telephony includes terminals for connection to a telephone line, a connection and power supply branch for a control circuit extending from a first terminal, the branch having a first switch, the cathode terminal of a first Zener diode and the source terminal of a first MOSFET transistor being connected to the output terminal of the first switch, the gate terminal of the first MOSFET transistor being connected, through the anode terminal of the Zener diode, to the first terminal. The current absorbed by the device may be adjusted.

Abstract: The breakdown characteristics of a lateral transistor integrated in an epitaxial layer of a first type of conductivity grown on a substrate of an opposite type of conductivity and comprising a drain region formed in said epitaxial layer, are markedly improved without recurring to critical adjustments of physical parameters of the integrated structure by forming a buried region having the same type of conductivity of the substrate and a slightly higher level of doping at the interface between the epitaxial layer and the substrate in a zone laying beneath the drain region of the transistor.

Abstract: The breakdown characteristics of a lateral transistor integrated in an epitaxial layer of a first type of conductivity grown on a substrate of an opposite type of conductivity and comprising a drain region formed in said epitaxial layer, are markedly improved without recurring to critical adjustments of physical parameters of the integrated structure by forming a buried region having the same type of conductivity of the substrate and a slightly higher level of doping at the interface between the epitaxial layer and the substrate in a zone laying beneath the drain region of the transistor.

Abstract: An integrated device includes isolating regions of a first type of conductivity, each surrounding an epitaxial pocket of an opposite type of conductivity, and housing drain and source regions, and covered with an oxide layer housing gate regions and over which extend the source, drain and gate connections. For linearizing potential distribution at the epitaxial pocket--isolating region junction and close to the source regions beneath the connections, these regions are provided with a double chain of condensers embedded in the oxide layer and the terminal elements and the intermediate element of which are biased to predetermined potentials.

Abstract: Device for limiting the working voltage for mechanical switches in telephony includes terminals for connection to a telephone line, a connection and power supply branch for a control circuit extending from a first terminal, the branch having a first switch, the cathode terminal of a first Zener diode and the source terminal of a first MOSFET transistor being connected to the output terminal of the first switch, the gate terminal of the first MOSFET transistor being connected, through the anode terminal of the Zener diode, to the first terminal. The current absorbed by the device may be adjusted.

Abstract: An integrated device includes isolating regions of a first type of conductivity, each surrounding an epitaxial pocket of an opposite type of conductivity, and housing drain and source regions, and covered with an oxide layer housing gate regions and over which extend the source, drain and gate connections. For linearizing potential distribution at the epitaxial pocket-isolating region junction and close to the source regions beneath the connections, these regions are provided with a double chain of condensers embedded in the oxide layer and the terminal elements and the intermediate element of which are biased to predetermined potentials.