Yamaha Corporation

Nippon Gakki Seizo Kabushiki Kaisha

Katsuhiko Ishida

Takayuki Kohdaka

Toshiyuki Takahashi

Takashi Ogata

Takashi Yoshida

Yukichi Ono

A semiconductor device comprising a semiconductor chip substrate, an integrated circuit formed on a surface of the semiconductor chip substrate, and metal electrodes extending from the integrated circuit to at least one of the side surfaces of the semiconductor chip substrate. Occupation area on a wiring circuit board can be reduced. Damaged chips can be exchanged easily. When it is set vertically, heat radiation efficiency can be improved.

Semiconductor chip with electrodes on side surface

A digital-to-analog converter converts digital data in the floating-point representation into an analog signal. The mantissa part of the digital data is first converted into a first analog signal by an R-2R resistor ladder network. The first analog signal thus obtained is directly supplied to another r-2r resistor ladder network to produce second analog signals whose values are 2.sup.-N (N=0, 1, 2, . . . ) magnifications of the first analog signal. And, one of the second analog signals is selectively outputted in accordance with the exponent part of the digital data. A data converter is also provided for converting digital data in the form of a fix-point number into floating point data.

Floating point digital to analog converter with bias to establish range

A digital-to-analog converter (DAC) converts digital input data into an analog output signal with less harmonic distortion over an entire signal-level range. An exponent value detector detects from the digital input data the number of bits by which the digital input data is to be shifted to form a mantissa part thereof. A digital shifter shifts the digital input data in accordance with the output of the exponent value detector, and outputs the mantissa part which is then supplied to a mantissa-part DAC. The mantissa-part DAC comprises an R-2R resistor ladder network and outputs the result of DA conversion of the mantissa part to an exponent-part DAC. The exponent DAC shifts the output of the mantissa-part DAC by an amount determined by the output of the exponent value detector, and outputs the shifted signal as the analog output signal of this DAC. A control circuit is provided between the digital shifter and the mantissa-part DAC, which prevents, in accordance with the output of the exponent value detector, the least significant bits of the mantissa-part DAC from operatively functioning to thereby decrease the number of operable bits thereof when the magnitude of the digital input data is small.

Digital-to-analog converter

A junction field effect transistor of a vertical type having: a drain region having a first conductivity type; a gate region composed of branches formed on said drain region by a selective vapor deposition or liquidous phase deposition method and having a second conductivity type opposite to the first conductivity type of the drain region, at least that surface of each of the branches of the gate region which locates on the side opposite to the drain region side being covered with an insulating layer; and source regions formed between the respective branches of the gate region by conducting a further growth of said drain region. This field effect transistor has a sufficiently reduced area of P - N junction between the gate region and the respective source regions, resulting in a marked reduction in the junction capacitance. Besides, the insulated gate region with respect to the source regions give rise to a high gate-to-source breakdown voltage property.

Growing community of inventors

Hamamatsu, Japan

Katsuhiko Ishida