摘要:
A method for reducing the computation time and improving the productivity in designing high-performance microprocessor chips that have no failures—due to crosstalk noise. The technique allows a very fast calculation of tables of frequency-dependent circuit parameters needed for accurate crosstalk prediction on lossy on-chip interconnections. These tables of parameters are the basis for CAD tools that perform crosstalk checking on >10K critical nets on typical microprocessor chips. A fast table generation allows for rapid incorporation of design or processing changes and transition to more advanced technologies.
摘要:
A method of evaluating decoupling capacitor placement for Very Large Scale Integrated Chips (VLSI) is disclosed. Included in the method is an analysis of the usage for each decoupling capacitor, the distance from the devices, and the locations of the devices and decoupling capacitors. Also addressed are the orientations and size of the components.
摘要:
A method of evaluating decoupling capacitor placement for Very Large Scale Integrated Chips (VLSI) is disclosed. Included in the method is an analysis of the usage for each decoupling capacitor, the distance from the devices, and the locations of the devices and decoupling capacitors. Also addressed are the orientations and size of the components.
摘要:
A method for identifying and positioning sub-optimally positioned unit pins in a hierarchically designed VSLI chip without modifying unit placement, comprising: generating a flat data file, generating a first pin log using the flat data file including data for unit pins and for macro pins of a net, generating a second pin log using the flat data file including data for macro pins of the net, determining a minimal net length using the first pin log and determining a minimum net length using the second pin log, calculating the difference between the minimal net length determined using the first ping log and the minimal net length determmed using the second pin log, identifying sub-optimally positioned unit pins by comparing the calculated difference to a threshold, and repositioning the identified sub-optimally positioned unit pins.
摘要:
A multi emitter multi input BICMOS NAND circuit (30) is provided wherein an output node OUT connected to an output terminal (33) is coupled between pull up (31) and pull down (32) blocks. According to one embodiment of the present invention, the pull up block (32) is comprised of a plurality of identical basic cells, each comprised of a CMOS inverter (C31, C32) driving an NPN pull up transistor (T31, T32) mounted as an emitter follower. Logic signals (A31, A32) are applied on the inputs of the inverters (C31, C32), and the inverted signal (A31, A32) is available at the emitter of the emitter follower which corresponds to the output of the cell. All outputs are tied altogether to perform an OR function and are connected to said output terminal (33) to have a multi emitter like circuit. The pull down block (32) in this embodiment is comprised of 2 FETs (F31, F32) serially connected between said output node OUT and a discharge device such as a feedback NFET (Z) the gate of which is connected to said output node OUT. These 2 FETs are for driving a NPN pull down transistor (T), the collector of which is also connected to the output node OUT. The invention includes a number of other embodiments including a feedback inverter embodiment, a parasitic node discharge embodiment, and a BIFET latch embodiment.
摘要:
A method of evaluating decoupling capacitor placement for Very Large Scale Integrated Chips (VLSI) is disclosed. Included in the method is an analysis of the usage for each decoupling capacitor, the distance from the devices, and the locations of the devices and decoupling capacitors. Also addressed are the orientations and size of the components.
摘要:
Deterministic evaluation of coupling noise voltage is a function of many physical and electrical parameters such as wiring level, widths, spacing, net topologies, drv impedance and slew rates. This evaluation requires electrical modeling and subsequent circuit simulation to assess the sensitivities of these parameters. These sensitivities can be categorized as coupling guidelines that can be directly linked through extracted physical design data. This invention discloses the development and implementation of a technique for using a coupling guideline table early in the design of an integrated circuit when all the parameters generally required for coupling noise voltage calculations are not available. The steps include: creating a flat wire routing map of the integrated circuit, identifying the coupled wire segments on the integrated circuit, tracking wire interconnection patterns on the integrated circuit, deriving electrical parameters for the coupled wire segments, and generating a coupling guideline table with parameters for a plurality of electrical parameters. The parameters in the coupling guideline table are applied to the derived electrical parameters and a report is generated that lists the derived electrical parameters that fail to comply with the parameters in the coupling guideline table.
摘要:
A routing program length method for positioning unit pins in a hierarchically designed VLSI chip first identifies unit pin positions initially assigned in a hierarchical VLSI design that, if implemented, would increase the net length of the net of which the unit pins are a part. To identify unit pins, where the unit pin position assigned by the unit designer turns out to be a poor choice of position when the unit is integrated into the top level design, a “flat” file is created of the completed VLSI design with the units positioned on the chip, including their pin placements as assigned by the unit designers. The flat file includes not only top level unit data and unit-to-unit net data, but also macro data and macro net data integral to each unit design. The flat design data file is used to generate two pin logs; one pin log includes the Incremental lengths of each net including the incremental lengths associated with the unit pins (if any) assigned by the designers of the units. The other pin log is the same, except it does not include the unit pins and the incremental net length associated with the unit pins. A commercially available program, for example, a Minimum Spanning Tree (MST) program or a Steiner Minimal Tree program is run against every net; once against the nets in the pin log list that includes the pins assigned by the designers of the units, and once against the nets in the pin log list that does not include assigned unit pins. The output of interest of the MST (or similar program) run against the net files with and without pin assignments is a text file containing the net names, number of pins per net with and without unit pins and the difference between the net lengths with and without unit pin assignments. If the difference exceeds a threshold value a router program is run in isolation against each net without unit pins. Pins are placed where the wiring route for the net crosses each unit boundary.
摘要:
A BIFET logic circuit for quickly switching an output line from a high level to a reference level. The BICMOS circuit comprises a push-pull circuit including a first bipolar transistor for driving current into an output line, and a second bipolar transistor for sinking current from the output line; a CFET logic circuit for performing a logic function and including at least one N type FET for providing current to the base of the second bipolar transistor when a set of input lines to the CFET circuit has a first set of predetermined values; and a resistive means for connecting one of the source or drain of the at least one NFET to a power supply to provide a source of base current to the second bipolar transistor, even when the output line drops in voltage. This circuit is especially advantageous for driving low threshold CFET circuits. In a preferred embodiment, the circuit further includes a device for preventing a voltage differential of more than a predetermined amount between the base and emitter of the first bipolar transistor, to thereby ensure proper push-pull operation of the bipolar transistors.
摘要:
The invention pertains to semiconductor circuitry, and more particularly to a class of circuitry known as current controlled gate circuits for driving very large scale integrated circuit gate arrays; the novel circuit can achieve much lower speed-power products than other circuitry, such as the well known T.sup.2 L circuitry; the circuit includes push-pull drive and it provides negligible DC current in both DC states, that is, On and Off.