Abstract: A high-speed solid state buffer circuit and method for producing the same. A buffer circuit accepts logic input signals and transforms the signals to an output signal which can drive a heavy load. By using an output stage pull-up device that includes a parallel combination of an enhancement mode FET and a depletion mode FET, a solid-state buffer circuit with increased speed and output voltage swing is achieved. Most conveniently, the buffer takes the form of a logic inverter. However, the buffer can also be used to form a multiple input NOR gate. The circuit is most suitable for realization in GaAs technology.

Abstract: A method and apparatus for determining the layout of an integrated circuit, in accordance with timing constraints, by means of sizing the buffers in the layout. A nominal netlist for the layout of the integrated circuit is used to determine critical paths through the circuit. The time-critical paths are determined and the instances of the buffers along the path are resized so that the time delays in the time-critical paths are either brought within the predetermined timing criteria, or no further improvement in any time-critical path is possible.

Abstract: A method and apparatus for determining integrated circuit layouts of a random access memory (RAM) from a virtual circuit description and specification of a process technology. Starting with high-level descriptions of a circuit, a virtual geometric description of the circuit is developed in terms of reference points relative to a substrate surface. When the process technology is specified, the relationships among the reference points is determined, as in the layout of the RAM. These relationships account for variable sizing of circuit features and pitch matching of circuit features. A connectivity model and a simulation model of the RAM are also produced by the method and apparatus. These model can be used to verify that the RAM is connected as desired and has the desired performance.

Abstract: A method and apparatus for generating a multiport static random-access memory (SRAM) in an integrated circuit. The apparatus includes a tape drive for accepting parameters describing a particular technology process and a keyboard for accepting user specifications of a desired multiport RAM. The user specifications include the number of words the RAM is capable of storing, the number of bits comprising each word, the number of READ ports, and the number of WRITE ports. The apparatus includes a computer which has been programmed to automatically generate the layout of a RAM including a central memory array core, READ and WRITE address buffers and decoders, data input and output buffers, and sense amplifiers. In order to reduce the area covered by the RAM, the READ and WRITE address ports are generally positioned on opposite sides of the memory array core, but so that the number of ports on the opposite sides are as nearly equal as possible.

Abstract: A method and apparatus for determining integrated circuit layouts from a virtual circuit description and specification of a technology. Starting with high-level descriptions of a circuit, a virtual geometric description of the circuit is developed using a virtual grid described in terms of reference points relative to a substrate surface. The relationships among the reference points are expressed as fractions of variables that can also be used to define the design rules. When the technology is specified, the relationships among the reference points is determined, as in the layout of the integrated circuit.