摘要:
An X-Y grid tree clock distribution network for distributing a clock signal across a VLSI chip. Tunable wiring tree networks are combined with an X-Y grid vertically and horizontally connecting all the tree end points. No drivers are necessary at connection points of the tree end points to the X-Y grid. The final X-Y grid distributes the clock signal close to every place it is needed, and reduces skew across local regions. A tuning method allows buffering of the clock signal, while minimizing both nominal clock skew and clock uncertainty. The tuned tree networks provide low skew even with variations in clock load density and non-ideal buffer placement, while minimizing the number of buffers needed. The tuning method first represents a total capacitance of one or more of clock pin loads and twig wiring as a clustered grid load. Next, a smoothing of the clustered grid loads approximates the effect of the X-Y grid. Electrical simulation models are created for network components and clustered grid loads are substituted with smoothed clustered grid loads. A set of NSECTOR electrical net lists are next created by extracting a net list with associated X-Y grid wires cut to isolate each sector net list from its neighboring sectors. Each NSECTOR electrical net list is then tuned, wherein the smoothed clustered grid loads represent an approximation of the effects of the neighboring sectors of each NSECTOR electrical net list.
摘要:
An X-Y grid tree clock distribution network for distributing a clock signal across a VLSI chip. Tunable wiring tree networks are combined with an X-Y grid vertically and horizontally connecting all the tree end points. No drivers are necessary at connection points of the tree end points to the X-Y grid. The final X-Y grid distributes the clock signal close to every place it is needed, and reduces skew across local regions. A tuning method allows buffering of the clock signal, while minimizing both nominal clock skew and clock uncertainty. The tuned tree networks provide low skew even with variations in clock load density and non-ideal buffer placement, while minimizing the number of buffers needed. The tuning method first represents a total capacitance of one or more of clock pin loads and twig wiring as a clustered grid load. Next, a smoothing of the clustered grid loads approximates the effect of the X-Y grid. Electrical simulation models are created for network components and clustered grid loads are substituted with smoothed clustered grid loads. A set of NSECTOR electrical net lists are next created by extracting a net list with associated X-Y grid wires cut to isolate each sector net list from its neighboring sectors. Each NSECTOR electrical net list is then tuned, wherein the smoothed clustered grid loads represent an approximation of the effects of the neighboring sectors of each NSECTOR electrical net list.
摘要:
A method and system for reducing the computation complexity and improving accuracy of delay and crosstalk calculation in transmission-lines with frequency-dependent losses. An analysis tool based on restricted coupled-line topologies, simple two-dimensional to three-dimensional RLC matrix conversion, and use of prestored synthesized circuits that accurately capture frequency-dependent loss effects. The CAD tool can handle frequency-dependent resistive and inductive effects for coupled-interconnections on large microprocessor chips with >10K of critical nets. This is done in an interactive manner during the design cycle and allows first path fast product design.
摘要:
A test circuit for detecting a leakage defect in a circuit under test includes a test stimulus circuit operative to drive an otherwise defect-free, characteristically capacitive node in the circuit under test to a prescribed voltage level, and an observation circuit having at least one threshold and adapted for connection with at least one node in the circuit under test. The observation circuit is operative to detect a voltage level of the node in the circuit under test and to generate an output signal indicative of whether the voltage level of the node is less than the threshold. The voltage level of the node being less than the threshold is indicative of a first type of leakage defect, and the voltage level of the node being greater than the threshold is indicative of a second type of leakage defect.
摘要:
A test circuit for detecting a leakage defect in a circuit under test includes a test stimulus circuit operative to drive an otherwise defect-free, characteristically capacitive node in the circuit under test to a prescribed voltage level, and an observation circuit having at least one threshold and adapted for connection with at least one node in the circuit under test. The observation circuit is operative to detect a voltage level of the node in the circuit under test and to generate an output signal indicative of whether the voltage level of the node is less than the threshold. The voltage level of the node being less than the threshold is indicative of a first type of leakage defect, and the voltage level of the node being greater than the threshold is indicative of a second type of leakage defect.
摘要:
A method and system for an infrastructure for performance-based chip-to-chip stacking are provided in the illustrative embodiments. A critical path monitor circuit (infrastructure) is configured to launch a signal from a launch point in a first layer, the first layer being a first circuit. The infrastructure is further configured to create an electrical path to a capture point. The signal is launched from the launch point in the first layer. A performance characteristic of the electrical path is measured, resulting in a measurement, wherein the measurement is indicative of a performance of the first layer when stacked with a second layer in a 3D stack without actually stacking the first and the second layers in the 3D stack, the second layer being a second circuit.
摘要:
Disclosed is a method of minimizing clock uncertainty using a multi-level de-skewing technique. The method includes the steps of obtaining a chip wherein at least a portion of the chip has a regular array of buffers on multiple levels, the buffers being driven by first drivers and the first drivers being driven by second drivers; grouping the buffers in a first direction to create clusters with the same number of buffer inputs, wherein if there are not the same number of buffer inputs in each cluster, then adding dummy buffers to the cluster with a deficient number of buffer inputs; wiring outputs of the first drivers together in a second direction, wherein the first and second directions are orthogonal; and wiring outputs of the second together in the second direction.
摘要:
Disclosed is a method of minimizing clock uncertainty using a multi-level de-skewing technique. The method includes the steps of obtaining a chip wherein at least a portion of the chip has a regular array of buffers on multiple levels, the buffers being driven by first drivers and the first drivers being driven by second drivers; grouping the buffers in a first direction to create clusters with the same number of buffer inputs, wherein if there are not the same number of buffer inputs in each cluster, then adding dummy buffers to the cluster with a deficient number of buffer inputs; wiring outputs of the first drivers together in a second direction, wherein the first and second directions are orthogonal; and wiring outputs of the second together in the second direction.
摘要:
Sensors on the integrated circuit are used to detect the current operating state of the chip, such as frequency, voltage, temperature characteristics, or variation in the integrated circuit manufacturing process. In response, the integrated circuit may choose to modify operational parameters (such as frequency, voltage, or power-down states) in order to dynamically and autonomously maintain an optimal performance and/or power-efficiency operational point.
摘要:
A method of wire routing includes the steps of providing an array of cells on a semiconductor chip, determining a minimum distance location between a first clock point, an second clock point and a drive point for connecting to a connection point in the array of cells, and defining a wire path through an array of blockages disposed in the array of cells from the minimum distance location to the first clock point and from the minimum distance location to the second clock point to create a path for a wire for connecting the first clock point and the second clock point to a connection point such that skew is minimized between the starting clock point and the second clock point from the connection point when a clock signal is provided to the connection point from the drive point.