Abstract: Integrated circuit design uses a library of structured soft blocks (SSBs) composed of pre-defined sets of cells with their logic implementation and placement templates with their relative placement information. A compiler receives a circuit description which includes an instance of an SSB and unfolds the instance according to the placement template to generate a modified circuit description which includes the relative placement information. The placement of circuit objects is optimized while maintaining relative locations for cells of the SSB instance according to the relative placement information. The SSB may be hierarchical. Gate resizing of cells in the SSB instance may result in a change in its bounds. A timing optimization procedure for the modified circuit description may be carried out while hiding internal details of the SSB instance. For example, buffers may be inserted in nets external to the SSB instance while preventing insertion of buffers in any internal nets.

Abstract: Integrated circuit design uses a library of structured soft blocks (SSBs) composed of pre-defined sets of cells with their logic implementation and placement templates with their relative placement information. A compiler receives a circuit description which includes an instance of an SSB and unfolds the instance according to the placement template to generate a modified circuit description which includes the relative placement information. The placement of circuit objects is optimized while maintaining relative locations for cells of the SSB instance according to the relative placement information. The SSB may be hierarchical. Gate resizing of cells in the SSB instance may result in a change in its bounds. A timing optimization procedure for the modified circuit description may be carried out while hiding internal details of the SSB instance. For example, buffers may be inserted in nets external to the SSB instance while preventing insertion of buffers in any internal nets.

Abstract: A system for logic block timing analysis may include a controller, and storage in communication with the controller. The storage may provide delay-versus-conesize values of a logic block. The system may further include a fitting module to provide a delay-cone based upon the delay-versus-conesize values of the logic block. The system may also include a conesize parser that uses the delay-cone to provide delay values through the logic block. The conesize parser may be used to validate the design of the logic block by comparing the delay-cone with a desired cycle time.

Abstract: A system to identify timing differences due to logic block changes, the system may include a controller, and storage in communication with the controller. The controller may provide delay values of a previous logic block and a current logic block. The system may also include a timing-modeler to compare the delay values of the previous logic block with the current logic block for timing analysis. The system may further include an interface that provides a report based upon the previous logic block and the current logic block comparison.

Abstract: A system for logic block timing analysis may include a controller, and storage in communication with the controller. The storage may provide delay-versus-conesize values of a logic block. The system may further include a fitting module to provide a delay-cone based upon the delay-versus-conesize values of the logic block. The system may also include a conesize parser that uses the delay-cone to provide delay values through the logic block. The conesize parser may be used to validate the design of the logic block by comparing the delay-cone with a desired cycle time.

Abstract: A circuit for testing a differential current switching logic circuit of the type including: a bias potential, two resistors connected to the bias potential, and apparatus responsive to an input signal for sinking a first current through a selected one of the resistors so as to generate first and second differential output signals at the resistors. The circuit includes first, second, and third transistors, each having first and second terminals for conducting a current responsive to a signal applied to a control terminal. Apparatus are provided for supplying a current. The first transistor has its first terminal connected to the current supplying means, and its second terminal connected to a circuit node. The second transistor has its first terminal connected to the circuit node, its second terminal connected to the bias potential, and its control terminal connected to sense the potential at a selected one of the resistors.