Abstract: Disclosed is a module (10) having pins (16-24) connected to respective conductor tower strips (46, 48, 50, 52). Pairs (46, 50 and 48, 52) of the conductor tower strips are spring biased toward each other to capture therebetween respective PTC current limiting elements (64, 70). A spring member 60 is connected to a ground pin (24) at one end, and to an overvoltage sensitive assembly at the other end, via a soldered heat transfer member (92). The overvoltage sensitive assembly includes overvoltage semiconductor devices (76, 77, 79) soldered thereto. When an overvoltage condition is sensed, the heat generated by the devices melts the solder between the heat transfer member (92) and the spring member (60), whereby lateral arms (90) of the spring member (60) move and engage the conductor tower strips (50, 52). The tip and ring pins (16, 18) of the module (10) are not only shorted together, but are shorted to ground.

Abstract: A semiconductor thyristor device that incorporates buried region breakdown junctions laterally offset from an emitter region. By spacing the buried regions around the emitter region, current carriers emitted from the buried regions are distributed over a large area of the emitter region, thereby providing a high current capability during initial turn on of the device. In order to achieve low breakover voltage devices, the buried regions are characterized with high impurity concentrations, with the breakdown junctions located near the surface of the chip. The low voltage thyristor device minimizes the area of high dopant concentration junctions, thus minimizing the chip capacitance and permitting high speed, low voltage signal operation.

Abstract: A thyristor provides overcurrent protection to a low impedance load, such as a transformer, by adding a resistance in series with the transformer winding. As overcurrents attempt to pass through the transformer winding, a sufficient voltage is generated in the transformer so that a thyristor connected thereacross is triggered into conduction. A resistance formed between the thyristor gate and cathode establishes the threshold of current that can pass through the transformer winding before the thyristor is triggered. When triggered into conduction, the thyristor shunts the current and the transformer is thus protected.

Abstract: A semiconductor device with two epitaxial layers formed on a substrate. The middle layer of epitaxial material can be formed thin and with an appropriate doping concentration to provide a low avalanche breakdown voltage with a negative resistance characteristic. The top layer of epitaxial material is doped with the same concentration as the substrate to provide a two-terminal thyristor device with symmetrical bidirectional operating characteristics.

Abstract: A semiconductor thyristor device incorporates buried regions to achieve low breakover voltage devices, and the buried regions are offset laterally with respect to the emitter regions. The low voltage thyristor devices can be incorporated into five-pin protection modules for protecting customer circuits.

Abstract: An integrated circuit (40) providing overvoltage and overcurrent protection to a line (16). The integrated circuit (40) is constructed to provide overvoltage protection when a voltage exceeding a specified magnitude is impressed across the cathode and anode terminals (64, 66), irrespective of the gate-cathode current. A gate terminal (72) is provided to trigger the overvoltage protection device into conduction when a gate current exceeding a predefined value is carried on the line (16). The gate-cathode structure of the integrated circuit (40) includes a semiconductor resistance (74) which functions to make the gate current required for turn on higher, thereby allowing the gate-cathode terminals (64, 72) of the integrated circuit (40) too be connected in series with the line (16) to be protected.

Abstract: A telephone line protection element constructed of three lead frames having contact fingers for holding therebetween a semiconductor cell providing overvoltage protection between the telephone line and the customer circuits. The lead frames are soldered to a resistive semiconductor material to provide a fail-safe mechanism that mechanically connects either the tip or ring telephone line conductors to ground if a sufficient overcurrent exists. In response to an overcurrent, the resistive semiconductor material generates heat and melts the solder in contact therewith, which allows a pre-bent member of the lead frame to move in contact with a ground terminal, thereby shunting the overcurrent to ground. The entire protection element includes very few components and is efficiently assembled and attached to the pins of a 5-pin module.

Abstract: A telephone line protection module having a printed circuit board base with conductive paths connected to pins of the module. Overvoltage sensitive semiconductor devices are soldered to the ends of a conductive bridge, and the bridge is spring-biased between a module cover and the conductive bridge. The semiconductor devices are thus forced into electrical contact with the printed circuit paths. In addition, in the event the semiconductor devices are thermally destroyed, the conductive bridge is forced by the spring into direct contact with the printed circuit paths.

Abstract: A semiconductor device soldered to a conical mounting pedestal of a metal substrate reduces the lateral shearing stress created by temperature changes. An angle between the bonding surfaces of the semiconductor device and the metal substrate can be selected as a function of the coefficients of thermal expansion of the device and substrate materials.

Abstract: A four-layer low voltage thyristor device (30) in which the breakover voltage is independent of the holding current. Rather than forming a buried region (38) underlying the emitter region (42), the buried region 38 is formed laterally to the side of the emitter (42). In order to form a low breakover voltage device, the buried region (38) is required to be highly doped, but the resulting junction (40) does not approach the emitter junction (48). A low breakover voltage (5 V-12-V) thyristor can thus be realized.

Abstract: A telephone line protection module having a printed circuit board base with conductive paths connected to pins of the module. Overvoltage sensitive semiconductor devices are soldered to the ends of a conductive bridge, and the bridge is spring-biased between a module cover and the conductive bridge. The semiconductor devices are thus forced into electrical contact with the printed circuit paths. In addition, in the event the semiconductor devices are thermally destroyed, the conductive bridge is forced by the spring into direct contact with the printed circuit paths.