Open-Silicon, Inc., (Open-Silicon) has completed two complex ASIC designs. The designs, which included large numbers of integrated high-speed serializer/deserializer (SerDes) cores, demonstrate its high-end digital IC design capabilities and ability to integrate complex open market IPc. The first chip is not yet announced and integrates over 50 SerDes for a networking application.
While the company has worked on a total of 30 ASICs with SerDes to date, the high lane count of these two recently completed devices made them particularly challenging in the areas of timing closure, package design, test, and physical design for signal integrity.
An additional challenge was imposed by the addition of high speed DDR2 interfaces. To handle all the high-speed IO requirements this chip was packaged in a custom HFCBGA package.
The second of the chips is a parallel graphics unit for gaming and computing designed with LucidLogix Technologies. This ASIC serves as a scalable graphics component connecting a main computer processor to multiple GPUs. A 12-quad 48-channel 2.5Gbps PCIe SerDes network is used to divide graphics processing work among several graphical processing units (GPUs). On this device the PCI Express lanes were spread evenly on all four sides of the die to facilitate use of low-cost wirebond packaging. As a single reference clock feeds all 48 lanes, a novel clock buffer ring was built outside the chip’s bond pads to isolate the clock from on-chip noise. Due to the high numbers of SerDes lanes, both designs required careful attention to:
Co-design of custom package with die physical design
Physical design taking into account the macro placements and signal interactions at very high speeds
Extensive SPICE level analysis of critical paths to analyze timing and cross-talk for the large number of SerDes lanes
Careful design of power sources to bring power to the macros
Verification early in the design phase that the SerDes DFT structures and Automated Test Equipment (ATE) will be able to provide complete and accurate test for production
High-end 3D graphics processing depends on silicon solutions that require a high degree of design expertise, said Offir Remez, president and vice president of business development for Lucid Information Technologies. The Open-Silicon design team tackled our tough chip requirements and met our specifications.