Abstract: A switching control circuit includes a level shifter that generates a switching control signal for a switching circuit, and a voltage generation circuit. The voltage generation circuit includes a first oscillator that generates a first oscillating signal, a frequency spectrum of which is controlled to be spread spectrum based on a second oscillating signal different from the first oscillating signal, and a power supply circuit that generates a power supply voltage based on the first oscillating signal and supplies a converted power supply voltage to the level shifter.

Abstract: According to an embodiment, a semiconductor device includes a switch circuit selecting a signal pathway between a common terminal and one of a plurality of terminals using a plurality of FETs provided in series between the common terminal and each of the terminals. The semiconductor device also includes a test switch including a plurality of FETs connected to the common terminal, an oscillation circuit connected to the common terminal via the test switch, and a detection circuit receiving an output of the oscillation circuit.

Abstract: An optical communication module according to an aspect of this invention includes: a module casing; a conversion element housed in the module casing, and performing at least one of conversion from an electric signal to an optical signal and conversion from an optical signal to an electric signal; a signal processing circuit element performing signal processing, which is housed in the module casing and connected to the conversion element; and a heat conduction member, which contacts the module casing and the signal processing circuit element when a temperature of the atmosphere in the module casing is above the operational temperature range of the signal processing circuit element, but which parts from the signal processing element when a temperature of the atmosphere in the module casing is below the operational temperature range.