Abstract: An optical transmission system including an optical transmission device and an optical reception device that receives, via an optical transmission line, a signal transmitted from the optical transmission device, the optical transmission system including a transmission-mode selection unit that selects transmission mode information in descending order of priority out of transmission mode information, which is combinations of a plurality of parameters concerning transmission performance, the transmission mode information being a plurality of kinds of the transmission mode information common to the transmission performance of the optical transmission device and the optical reception device, a signal transmission unit that transmits, to the optical reception device, a signal modulated based on the selected transmission mode information, and a signal reception unit that receives the signal and modulates the received signal based on the transmission mode information selected by the transmission-mode selection unit.

Abstract: A circuit device connected between a neighboring pair of terminals in a semiconductor integrated circuit is protected from electrostatic damage due to a surge voltage when the surge voltage is applied between the neighboring pair of terminals. The semiconductor integrated circuit is formed to include terminals P0-P14, MOS transistors MN0-MN15 in diode connection, protection diode circuits HD0-HD14, MOS transistors T1-T14 for discharging electricity from batteries, a battery voltage detection control circuit and a clamp circuit for overvoltage protection. Each of the MOS transistors T1-T14 for discharging electricity from the batteries is connected between each neighboring pair of the terminals P0-P14 through wirings. Each of the MOS transistors MN1-MN14 in diode connection is connected between each neighboring pair of the terminals.

Abstract: An ESD tolerance of an LDMOS transistor is improved. An N+ type source layer shaped in a ladder and having a plurality of openings in its center is formed in a surface of a P type base layer using a gate electrode and a resist mask. A P+ type contact layer is formed to be buried in the opening. At that time, a distance from an edge of the opening, that is an edge of the P+ type contact layer, to an edge of the N+ type source layer is set to a predetermined distance. The predetermined distance is equal to a distance at which an HBM+ESD tolerance of the LDMOS transistor, which increases as the distance increases, begins to saturate.

Abstract: An ESD tolerance of an LDMOS transistor is improved. An N+ type source layer shaped in a ladder and having a plurality of openings in its center is formed in a surface of a P type base layer using a gate electrode and a resist mask. A P+ type contact layer is formed to be buried in the opening. At that time, a distance from an edge of the opening, that is an edge of the P+ type contact layer, to an edge of the N+ type source layer is set to a predetermined distance. The predetermined distance is equal to a distance at which an HBM+ESD tolerance of the LDMOS transistor, which increases as the distance increases, begins to saturate.

Abstract: A circuit device connected between a neighboring pair of terminals in a semiconductor integrated circuit is protected from electrostatic damage due to a surge voltage when the surge voltage is applied between the neighboring pair of terminals. The semiconductor integrated circuit is formed to include terminals P0-P14, MOS transistors MN0-MN15 in diode connection, protection diode circuits HD0-HD14, MOS transistors T1-T14 for discharging electricity from batteries, a battery voltage detection control circuit and a clamp circuit for overvoltage protection. Each of the MOS transistors T1-T14 for discharging electricity from the batteries is connected between each neighboring pair of the terminals P0-P14 through wirings. Each of the MOS transistors MN1-MN14 in diode connection is connected between each neighboring pair of the terminals.