Fujitsu Corporation

Fujitsu Semiconductor Limited

Tatsuhiro Mizumasa

Koji Nozoe

Atsushi Hitaka

Susumu Koshinuma

Takayuki Nakashiro

Yuji Maruyama

Takayuki Yano

Shunsuke Taniguchi

Shigeru Gotoh

Yuki Yanagisako

According to the following disclosure, disclosed is a semiconductor device including: an internal circuit configured to receive and output a signal current; a current mirror unit outputting a copied current corresponding to the signal current; and a test pad from which the copied current is taken out.

Semiconductor device and method of testing semiconductor device

A cutoff frequency adjusting method adjusts a cutoff frequency of a GmC filter circuit which has a capacitor and an Operational Transconductance Amplifier (OTA) circuit with a controllable Gm value. A Gm value of the OTA circuit is detected based on a voltage of the capacitor which is charged by an output of the OTA circuit, and a cutoff frequency of the GmC circuit is set to a desired value by controlling the Gm value of the OTA circuit constant based on the detected Gm value.

Cutoff frequency adjusting method, GmC filter circuit and semiconductor device

A filter circuit, having a plurality of selectable impedance elements, that has a cutoff frequency dependent on a selected impedance element, comprises a pulse generation circuit that supplies a variable frequency pulse with a successively increasing or decreasing frequency to an input of the filter circuit; and an impedance element selection unit that checks the attenuation of the output pulse of the filter circuit corresponding with the input of the variable frequency pulse and selects the plurality of impedance elements on the basis of the position of a pulse that is attenuated to or below a reference value.

Filter circuit permitting adjustment of cutoff frequency

A frequency detecting circuitdetects frequency of a sampling pulse SP, and outputs the detected frequency as a detection value VOUT. A current adjusting circuitadjusts a power supply current Ivd to be supplied to an AD converterin accordance with the detection value VOUT. The power supply current Ivd varies continuously so as to follow the sampling frequency. As a result, an optimum power supply current Ivd can always be supplied in accordance with the operating frequency of the AD converter. That is, power consumption of the AD convertercan be reduced. Since the power supply current Ivd can be adjusted in accordance with the sampling frequency, it is possible to form the AD converterthat has a wide frequency band and allows great versatility.

Semiconductor integrated circuit

A semiconductor integrated circuit has a first circuit region using a first power supply voltage and a second circuit region using a second power supply voltage different from the first power supply voltage. The first circuit region is manufactured by a first design rule in accordance with the first power supply voltage, and the second circuit region is manufactured by a second design rule in accordance with the second power supply voltage.

Semiconductor integrated circuit having a plurality of circuit regions where different power supply voltages are used and method of manufacturing the same

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Kawasaki, Japan

Tatsuhiro Mizumasa