Stratix® II GX device transceivers build on the success, reliability, low power, and jitter performance of the Stratix GX device transceivers to provide a robust solution for many of the new applications emerging today. The transceivers integrate both an enhanced analog physical medium attachment (PMA) block and digital physical coding sub-layer (PCS) block. The PMA includes technology to aid signal integrity, reducing PCB layout risk. The PCS integrates dedicated features to reduce the FPGA overhead when supporting a number of key protocols.
Differences Within the PMA
The key difference between Stratix GX and Stratix II GX transceivers is the data rate. The Stratix II GX transceiver provides a native data range of 600 Mbps to 6.375 Gbps, while again supporting data rates as low as 270 Mbps with over-sampling. The data range was specifically chosen to support the majority of current and planned protocols and applications suitable for FPGAs. This targeted approach allows Altera to provide the optimum transceiver with exceptional jitter performance, but with the lower power consumption expected for backplane and inter-chip communication applications.
Support for data rates beyond 3.125 Gbps require specialist features in the transceiver to ensure successful data transmission, particularly if a higher data rate is to be achieved within an existing system. The Stratix II GX transceiver provides high levels of pre-emphasis and equalization with granular control to address this. Tools are available to simplify selection.
Stratix II GX FPGAs provide considerably more logic, memory, and digital signal processing (DSP) functionality than Stratix GX FPGAs in addition to the higher data rate transceivers. It is therefore necessary to provide more I/O circuitry for memory interfacing and high-speed source-synchronous LVDS signaling to cater for the increased complexity and the higher bandwidth from the transceivers. The increased number of I/O pins has led to significant efforts to manage simultaneous switching noise (SSN). Stratix II GX transceivers adopt a number of techniques to manage output SSN including a higher power and ground to I/O pin ratio combined with carefully designed packages.
Figure 1 shows the key differences between Stratix GX and Stratix II GX transceivers.