Abstract: An oscillation section for which an output frequency is controlled based on a control signal depending on an ambient temperature; a temperature compensation circuit for supplying the control signal to this oscillation section; and a switching switch circuit consisting of an output buffer and a temperature sensor output switch for which ON and OFF are controlled so that any one of an oscillation output from the oscillation section and a temperature sensor output from the temperature compensation circuit is outputted. The temperature sensor output switch is structured so that transfer gate switches are connected in a two-stage serial manner and a third switch connected to a fixed potential is sandwiched between these connection points. When an oscillation output is outputted, the transfer gate switches are OFF and the third switch is ON and, when a temperature sensor output is outputted, the transfer gate switches are ON and the third switch is OFF.

Abstract: An oscillation circuit of the present invention includes: an oscillation section for which an output frequency is controlled based on a control signal depending on an ambient temperature; a temperature compensation circuit for supplying the control signal to this oscillation section; and a switching switch circuit consisting of an output buffer and a temperature sensor output switch for which ON and OFF are controlled so that any one of an oscillation output from the oscillation section and a temperature sensor output from the temperature compensation circuit is outputted. The temperature sensor output switch is structured so that transfer gate switches are connected in a two-stage serial manner and a third switch connected to a fixed potential is sandwiched between these connection points. When an oscillation output is outputted, the transfer gate switches are OFF and the third switch is ON and, when a temperature sensor output is outputted, the transfer gate switches are ON and the third switch is OFF.

Abstract: A frequency synthesizer comprises a digital/analog converter which sequentially converts difference data of phase data indicating the phase of a reference signal to an analog value, a voltage signal generator which integrates the analog value converted by the digital/analog converter, thereby generating a voltage signal interpolating between signal levels corresponding to two time-sequential pieces of the phase data, a reference-timing-signal output section which outputs a reference timing signal indicating the specific phase of the reference signal at a timing when the signal level of the voltage signal generated by the voltage signal generator crosses a preset setting voltage, and a reset section which resets the voltage signal generated by the voltage signal generator to the setting voltage. Accordingly, the noise performance of an output signal from the frequency synthesizer is improved.

Abstract: A frequency synthesizer comprises a digital/analog converter which sequentially converts difference data of phase data indicating the phase of a reference signal to an analog value, a voltage signal generator which integrates the analog value converted by the digital/analog converter, thereby generating a voltage signal interpolating between signal levels corresponding to two time-sequential pieces of the phase data, a reference-timing-signal output section which outputs a reference timing signal indicating the specific phase of the reference signal at a timing when the signal level of the voltage signal generated by the voltage signal generator crosses a preset setting voltage, and a reset section which resets the voltage signal generated by the voltage signal generator to the setting voltage. Accordingly, the noise performance of an output signal from the frequency synthesizer is improved.

Abstract: A semiconductor device has a DRAM portion forming a cache memory and a flash memory portion fabricated on a common substrate, fabricated by a process based on the process of fabricating the flash memory portion. An electrode layer common to capacitors of the DRAM portion and a floating gate layer of the flash memory portion are formed simultaneously from the same material. An electrode layer of the upper capacitor of the DRAM portion, a gate electrode layer for a transistor of the DRAM portion, and a control gate layer of the flash memory portion are formed simultaneously from the same material.

Abstract: A method of making a semiconductor device having formed thereon an inductor comprises a silicon substrate. A cut out region is obtained by removing a part of the silicon substrate in a hollow shape which may be a hollow cavity or a hollow cavity with an insulating material having a low complex permittivity such as silicon oxide buried therein. An insulator layer is formed on the cut out region and on the periphery thereof. A connection layer serves as one of the leads of the inductor and is formed using an electric conductive material such as a metal or doped polycrystalline silicon. A contact hole is provided in the interlayer insulation layer. A connection layer serves as an inductor and the other lead of the inductor, which is formed using an electric conductive material such as a metal. A protective insulator layer is also provided on the top of the structure.