Motorola Corporation

Freescale Semiconductor,inc.

Takashi Kumazaki

Masami Aiura

Yuichi Nakatani

Kenichi Watanabe

Akira Shoji

A flip flop device, a semiconductor integrated circuit, and a method and apparatus for designing a semiconductor integrated circuit that prevents timing violations while preventing the circuit scale from increasing. A flip flop including first, second, and third latch circuits is stored as a standard cell in a cell library of a designing apparatus. The output of the second latch circuit becomes a first output signal of the flip flop. The second latch circuit provides the third latch circuit with a signal generated by latching a data signal with a clock signal. An output of the third latch circuit becomes a second output signal of the flip flop. When an error path having the possibility of a hold time violation is found, output of the flip flop in a former stage is changed from the first output to the second output in the error path.

Method and apparatus for designing semiconductor integrated circuit

A digital-to-analog conversion circuit including a plurality of unit current output cells ( ) arranged in a matrix. Each of the current output cells ( ) includes a unit current source ( ) having a power supply input and a current output, and a selecting switch ( ) connected to the current output and having two switching output terminals. The circuit further includes at least one &frac12; and/or &frac14; weighted current output cell ( ) disposed on a row in the matrix, and at least one &frac12; and/or &frac14; supplementary current source ( ) disposed on a desired row so that the total current consumption of the unit, weighted and supplementary current sources on each row is substantially the same. A decoder responds to a digital signal to control the switching of the selecting switches one by one as the digital signal gradually increases.

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Sendai, Japan

Takashi Kumazaki