Bruce B. Pedersen

The Stratix II logic and routing architecture

This paper describes the Altera Stratix II™ logic and routing architecture. This architecture features a novel adaptive logic module (ALM) that is based on a 6-LUT, but can be partitioned into two smaller LUTs to efficiently implement circuits containing a range of LUT sizes that arises in conventional synthesis flows. This provides a performance increase of 15% in the Stratix II architecture while reducing area by 2%. The ALM also includes a more powerful arithmetic structure that can perform two bits of arithmetic per ALM, and perform a sum of up to three inputs. The routing fabric adds a new set of fast inputs to the routing multiplexers for another 3% improvement in performance, while other improvements in routing efficiency cause another 6% reduction in area. These changes in combination with other circuit and architecture changes in Stratix II contribute 27% of an overall 51% performance improvement (including architecture and process improvement). The architecture changes reduce area by 10% in the same process, and by 50% after including process migration.

The stratixπ routing and logic architecture

This paper describes the Altera Stratix logic and routing architecture. The primary goals of the architecture were to achieve high performance and logic density. We give an overview of the entire device, and then focus on the logic and routing architecture. The Stratix logic architecture is based on a cluster of ten 4-input LUTs and its routing consists of staggered routing lines. We describe the development of the routing architecture, including its directional bias, its direct-drive routing which reduces both area and delay. The logic array block and logic cell design is also described, and new routing structures with in the logic array block, and logic element features are described.

Improving FPGA Performance and Area Using an Adaptive Logic Module

This paper proposes a new adaptable FPGA logic element based on fracturable 6-LUTs, which fundamentally alters the longstanding belief that a 4-LUT is the most efficient area/delay tradeoff. We will describe theory and benchmarking results showing a 15% performance increase with 12% area de- crease vs. a standard BLE4. The ALM structure is one of a number of archi- tectural improvements giving Alteras 90nm Stratix II architecture a 50% per- formance advantage over its 130nm Stratix predecessor.

A dual granularity and globally interconnected architecture for a programmable logic device

A novel architecture called FLEX (flexible logic element matrix) has been designed which supports high logic densities up to 24,000 gates, maximizing overall system performance in a user design. This has been accomplished through a dual granularity approach and a global interconnect strategy. The dual granularity and global interconnect approach has succeeded in supporting both short nets and long nets for maximum performance.

Interconnect enhancements for a high-speed PLD architecture

As programmable logic grows more viable for implementing full design systems, performance has become a primary issue for programmable logic device architectures. This paper presents the high-level design of Dali, a PLD architecture specifically aimed at performance-driven applications. We will present significant portions of the background research that contributed to our architectural decisions, an overview of the core routing architecture and benchmarking experiments used to evaluate the prototype device.

A next generation architecture optimized for high density system level integration

Altera has developed a next generation architecture called APEX/sup TM/ to improve overall logic efficiency, performance and provide a framework to add a much broader range of features which enables complete system level integration of a users system. This new architecture will support a family of devices exceeding 2 million gates in density. Density and speed improvements are achieved through an enhanced hierarchical routing structure.

Optimizations for a highly cost-efficient programmable logic architecture

Architects of programmable logic devices (PLDs) face several challenges when optimizing a new device family for low manufacturing cost. When given an aggressive die-size goal, functional blocks that seem otherwise insignificant become targets for area reduction. Once low die cost is achieved, it is seen that testing and packaging costs must be considered. Interactions among these three cost contributors pose trade-offs that prevent independent optimization. This paper discusses solutions discovered by the architects optimizing the Altera FLEX 6000 architecture.

A silicon efficient FLEX 6000 programmable logic architecture

An SRAM based PLD architecture ranging from 5000 to 24000 gates has been developed. The primary focus of the architecture is on low cost, high performance, and routability. Breakthroughs in interconnect scheme have been made to achieve flexible routing and high cost efficiency in the interconnect, logic array blocks, and I/O elements. Other architecture features include built-in low skew clock, programmable output slew rate control, PCI compliant I/O, JTAG boundary scan, individual output enable for each I/O pin, and in-circuit configuration. The first member of the family is currently available with 16000 gate density and 125 MHz performance for 16-bit counter application.