As device geometries shrink, the supply voltage has to be lowered to ensure reliable performance. If the current market trends in manufacturing technologies are any indication, then it is safe to predict that by the end of 1999, 0.18-micron technologies will be in volume production, and 0.12-micron technologies will be in development. High-performance driven products such as microprocessors and ASICs will lead the way, with PLD technology following closely on their heels. So to gain a performance edge while maintaining low costs, PLDs will move toward smaller geometries and lower supply voltages as other industry-standard products have.
If a design requires a higher-density device to fit more logic, it's likely that this will be available only with a 3.3-V or lower supply voltage. To design with higher-density devices, a designer must consider supply-voltage compatibility as well as other ease-of-use features such as pin locking and routability. Most PLD suppliers offer low-voltage families that range from low densities to high densities with pin-locking capabilities, facilitating the transition to larger designs.
As designs migrate to lower supply voltages, PLD vendors are developing ways to manufacture lower-voltage devices. Most PLDs on the market still operate at 5 V, but in the past few years, the availability of 3.3-V devices has become more prominent. Suppliers are introducing next-generation families manufactured on leading-edge process technologies. In general, these families offer higher-performance, feature-rich devices with 3.3-V supply voltages.
Altera, Vantis, Lattice, Xilinx, Philips and Cypress all announced that new low-voltage families are available in production quantities in 1999.
Altera currently offers low-voltage CPLDs across two product families, the MAX7000 as well as the newer-generation MAX7000A. The MAX7000 family is a 5-V family with one 3.3-V member, the 32-macrocell device. The MAX7000A is Altera's high-performance, low-voltage family, currently offering three macrocell densities (64, 128 and 256), with plans to complete the family (32, 384 and 512 macrocells) this year. This family has the capability of interfacing with 5-, 3.3- or 2.5-V logic, is in-system-programmable through the JTAG interface, has JTAG testability and hot socketing.
Lattice has two families with 3.3-V operation, the ispLSI2000V and the new ispLSI500V. The ispLSI2000V family is available in 32, 64, 96 and 128 macrocells and can interface with 5-V logic. The ispLSI500V family is based on Lattice's new architecture and is only available in 384 macrocells. The 256- and 512-macrocell devices are planned for release this year. This family can interface with 5-, 3.3- and 2.5-V logic.
Xilinx has one low-voltage device line, the XC9500XL, which is an extension of its 5-V family. Currently, only the 144-macrocell device is available, with plans to expand this family with three more devices (36, 72 and 288 macrocells) this year. This family can interface with 5-V, 3.3-V and 2.5-V logic.
Philips' low-voltage CoolRunner family is available in densities of 32, 64, 128 and 960 macrocells, with plans to add the 320-macrocell density device this year. These devices are currently not 5-V tolerant. Future enhancements will incorporate this feature.
Cypress has a low-voltage line, the Ultra37000, spanning 32 to 512 macrocells, with 192- and 256-macrocell devices now available.
Vantis offers 3.3-V support with the Mach 4 and Mach 5 lines. There are 12 members of the new high-performance Mach 4A family (32, 64, 96, 128, 192, 256, 384 and 512 macrocells). The Mach 5A line has 23 devices with macrocell densities of 128, 192, 256, 320, 384 and 512.
With all of today's feature-rich 3.3-V CPLDs, designers have a range of choices. Like CPLDs, most FPGAs operate at 5 V. Today's top FPGA suppliers are Xilinx, Altera and Lucent, all offering 3.3-V (or lower) products.
Xilinx's two new series, the SpartanXL and the XC4000X, comprise the XC4000-XLA and XC4000XV lines. The SpartanXL line has five 3.3-V devices ranging from 5k to 40k system gates. The XC4000XLA has eight 3.3-V devices ranging from 13k to 180k system gates, and the XC4000XV is a 2.5-V family with five members offering 200k to 500k system gates. Now available, the XC4000-XL family offers 3.3-V operation with 11 devices ranging from 2k to 85k logic gates.
Altera speedup
Altera's Flex 10K family supports multiple operating voltages. The Flex 10KA family operates at 3.3 V and is available with 10k, 30k, 50k, 100k, 130k and 250k gates. The newest-generation family, the Flex 10KE, is 20 percent to 30 percent faster than the Flex 10KA and operates at 2.5 V. This is available with 50k gates, with plans to introduce devices up to 250k gates this year. Both families interface with 5-V, 3.3-V and 2.5-V devices.
Lucent supports 3.3-V FPGAs with its Orca line. The OR2T-A and OR3T families are available in 3.3 V. The OR2T-A family ranges from 4-k to 40-k logic gates and the OR3T family from 30-k to 165-k logic gates. Plans call for migrating the OR3T family to 2.5-V operation at 0.25 micron.
Vantis is also entering the FPGA market with its 3.3-V VF1 family of devices, which ranges from 12-k to 36-k logic gates and will be available this year. These devices are positioned as the industry's highest-performance FPGA family, supporting designs requiring high gate counts and fast system speeds.
