When a component is placed on a circuit board, a placement position is determined by method of elastic center. Then, it is determined whether the component was placed on the circuit board. After that, connectors are routed between the component and a design candidate component which is already placed. After that, the next component is set, and the above mentioned packaging processing is repeated.
Detail routing using obstacle carving around terminals. A terminal in an integrated circuit layout object that is separated from an obstacle by less than a spacing specified by a design rule is identified. The obstacle is carved to reduce an area of the obstacle by an overlap between the obstacle and the terminal bloated by the spacing.
A CAD apparatus includes a determining unit for determining a component order in ascending order of impedance of components for passive components amongst components to be placed on a printed wiring board. The CAD apparatus places each passive component in the determined component order in a vicinity of power pins of non-passive components that are already placed.
Method and apparatus for placement of vias is described. More particularly, source power and ground vias are placed in partial response to locations where conductive lines cross over a reserved region. The reserved region is reserved for an embedded device, and is reserved in a layout database of a host device.
In a method of recognizing a connection of a reconstructing pattern in a printed wiring board when a circuit modification process after a printed board wiring is performed by a physical cutting, a jumper, or the like, a physical connection table is prepared which has a forward connecting direction address (KP address) indicating a forward connection order of connecting elements (a land, a via, a manual land, an external land, a line, and a jumper) with a predetermined connecting element (the land) being made a starting point and a backward connecting direction address (NKP address) indicating a backward connection order to the forward connection order, based on a pattern input information table. Also, a large area pattern is regarded as one of a peripheral line, a punching line, an imaginary line, and a cutting line of the above-mentioned lines, whereby the connecting elements are made to include the large area pattern.
An apparatus for designing a printed wiring board comprises an input section for receiving information necessary to design the board, information on components to be mounted on the board, and information on connection between the components; a storage section for storing the information such as the board information, the component information, the connection information, and the information obtained form printed wiring boards designed in the past; a display section for displaying the input information and various information on designing; and a calculation/control section for performing predetermined calculations by the use of various information stored in the storage section and controlling the input section, the display section, and the storage section, wherein the ratio of a total wirable length to a total wiring length necessary to connect components is determined on the basis of various information stored in the section 38, and a PWB grade of the board is selected based on this ratio. A method of performing these calculations to obtain such results is also provided.
