First introduced in 1998, Xilinx® Spartan™ FPGAs were the world’s first FPGA series for low-cost applications. With the introduction of the Spartan-3E family, Xilinx now has seven families of Spartan FPGAs in production – with more than 135 million units shipped to date. The Spartan series features the world’s most widely implemented low-cost FPGA architectures, designed into high-volume applications by thousands of engineers.

The Spartan-3 Generation Is composed of the Spartan-3, Spartan-3L, and Spartan-3E FPGA families. The Spartan-3 family (introduced in 2003) is optimized for I/O-centric designs, and is ideally suited for systems that have large I/O requirements. The Spartan-3E family is optimized for gate-centric designs, and is well-suited for designs that require a relatively higher gate-to-I/O ratio. The older Spartan-II/IIE and Spartan-XL families remain suitable candidates for legacy designs or for systems with higher core voltages.

Spartan-3 Generation FPGAs have found remarkable success replacing ASIC and gate array devices. For example, many flat-panel display systems employ Spartan-3 devices to manage the display driver and control functions. The ability to modify the design after layout and adapt the system to changing market conditions makes FPGAs highly desirable.

The Spartan-3E Family

The Spartan-3E family is our newest low-cost FPGA family, and further reduces the price points for low-cost FPGAs to unprecedented levels. Through 90 nm process technology, 300 mm wafers, and application-driven architecture choices, Xilinx is extending the reach of FPGAs into volumes and applications previously reserved for mask-programmed ASICs and gate-arrays. With Spartan-3E devices providing the lowest cost-per-logic ( CPL) and Spartan-3 devices providing the lowest cost-per I/O ( CPI), the Spartan-3 Generation is meeting customer needs in low-cost system design.

Spartan-3E devices extend the reach of FPGAs into production volumes by further reducing costs, while preserving the low NRE and high flexibility of programmable logic. Many mainstream applications using Spartan-3E FPGAs will have an ASIC crossover point of 250,000 units – meaning that the total cost favors Spartan-3E devices over ASICs for the first quarter-million units of production.

The Spartan-3E FPGA architecture is primarily focused on cost reductions that benefit high-volume/low-cost applications, such as digital consumer electronics. Its advanced features add capabilities for new applications, and provide total cost reductions. For example, support for low-cost commodity SPI and parallel Flash memory means that configuration costs for Spartan-3E FPGAs are negligible for systems that already have this memory in place. Further, reducing the input lock frequency on the clock management circuitry to 5MHz allows low-cost low-speed consumer designs to employ lower-cost oscillators rather than higher-cost precision time sources.

Cost reductions are most strongly influenced by die size reductions. Spartan-3E FPGAs have a refined I/O layout and resized the output buffers to achieve a significant I/O pad size reduction over previous Spartan FPGA families. Even a small area reduction in each I/O adds up to a relatively large savings because it is repeated for each I/O pad. Many of the decisions in the Spartan-3E architecture were driven by direct feedback from high-volume and low-cost customers.

The five-member family ranges from the 100,000-gate XC3S100E through the 1.6 million-gate XC3S1600E. Table 1 illustrates the family members and key features of the Spartan-3E family.

Table 1: Spartan-3E Family Matrix

 New Features in Spartan-3E Devices
In addition to the optimized inline I/O ring, Spartan-3E FPGAs have a host of cost-reducing features including:

• Support for low-cost commodity SPI and parallel Flash configuration memory
• PCI 33/66 support
• DDR 333 memory interface
• Support for Mini-LVDS and RSDS display interface standards
• DCM clock frequency input range expanded down to 5 MHz (ideal for video)
• 270 MHz multipliers aligned with block RAM for low-cost DSP

Support for low-cost commodity SPI and parallel Flash configuration memories is one of the most important new features in Spartan-3E. These memories are generally very inexpensive, and are often already in place in many consumer and high-volume applications. Spartan-3E FPGAs can interface directly to a wide range of memories from different vendors, and with different features and capabilities. For example, Spartan-3E offers MultiBoot, the unique ability to have multiple patterns in a parallel Flash configuration memory without any additional external switching circuitry.

Morever, once the FPGA is configured it can use the SPI or parallel Flash memory as data and code storage for system functions, and even reprogram the memory directly. This is all done using generic I/O pins, so pins are lost to the configuration mechanism. The configuration memory is lower cost, and the Spartan-3E FPGA offers a wider range of features and capabilities – blending lower cost and increased value. And as with all of the Spartan FPGA families, Xilinx provides proprietary Platform Flash configuration PROMs with expanded features and capabilities that are ideal for certain applications and design requirements.

 The Most Valuable Feature: Programmability

Spartan series FPGAs have enabled entire new classes of applications, and made programmable systems more affordable for more design teams. The Spartan-3E family was designed for consumer applications, opening the promise of hardware customization to the mass market. Figure 3 illustrates just a few of the ways that the high-volume products from Xilinx (CoolRunner™-II CPLDs and Spartan series FPGAs) are being used in consumer applications.

 Figure 3: High Volume Designs that rely on Xilinx PLDs

Conclusion

With the arrival of the Spartan-3E FPGA family, there are now even more reasons to consider programmable logic in the production of low-cost systems. With device prices starting under $2 and numerous features that lower total system cost, Spartan-3E devices are the ideal production solution for increasing numbers of low-cost, high-volume, and consumer applications.

Prices quoted for Spartan-3E FPGAs are for 500K unit volumes, slowest speed grade, commercial temperature grade, lowest-cost packages, delivered in 2H2006.

November 17, 2005

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