Altera Corporation

Nafira Daud

Peter Boyle

Iliya G Zamek

Geping Liu

San Wong

Lawrence David Smith

Eugene V Gomez

A method for optimizing pin selection for an integrated circuit is provided. Pin locations are mapped to a vector. The mutual inductive relationships between pins of the integrated circuit are captured into a matrix. The matrix contains the data of how a signal state of each pin is affected by the toggling of other pins within the I/O bank. The pin locations and the crosstalk matrix are combined to characterize the impact of the crosstalk on the pins for the pin placement. Thereafter, a user may decide to alter the pin placement or alter the sampling interval for the pin to avoid sampling the pin when the crosstalk may affect the signal integrity. The method may be applied for multiple simultaneous switching noise cause mechanisms impacting the signal integrity. In this embodiment, a worst case cause mechanism from the individually quantified cause mechanisms is determined by comparing an impact of each of the cause mechanisms.

Method and system for analyzing input/output simultaneous switching noise

Integrated circuits contain core logic that is powered using a power supply signal. The core logic contains simultaneously switching circuitry. The simultaneously switching circuitry contributes to noise on the power supply signal. Balancing circuitry may be provided on the integrated circuit to compensate for the simultaneously switching circuitry in the core logic. The balancing circuitry may receive an input signal that is out of phase with respect to the input to the core logic. As the balancing circuitry switches out of phase with the simultaneously switching circuitry of the core logic, the noise contribution from the core logic is compensated and power supply noise on the power supply signal is minimized.

Integrated circuits with jitter-reducing balancing logic

A jitter calculator engine that includes a core effects module, an input/output (I/O) module, and a phase lock loop (PLL) module is provided. The core effects module estimates core jitter caused by noise effects impacting a core clock network. The I/O module estimates I/O input pin switching effects on a clock network input signal. In one embodiment, the I/O module identifies a relative frequency of switching by I/O pins in the circuit design. The PLL module estimates an effect of a PLL on a signal delivered to the PLL from an I/O pin. The PLL module accounts for I/O input pin switching effects and core jitter. The jitter calculator engine may be in communication with a database and the different designs evaluated may be stored in the database so that the database becomes a repository for the different designs and may provide useful information for future designs.

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Pleasanton, CA, United States of America

Nafira Daud