Smart serial data cable speed rate
The same effect can be seen across category, with optical transmission leading the other categories following. SGMII, 1Gb Ethernet, 10Gb Ethernet, 25/100Gb EthernetĪs would be expected, line rate has been increasing at an exponential rate.These serial standards are shown above in Figure 1. The following set of plots show the rollout of various serial data standards and the state of SERDES research. Perhaps the most important example of this is PCIe, which was introduced around 2002 at 2.5Gbps and became popular in the mid-2000s. This development would turn SERDES from an important long-distance communications circuit into a critical SoC component. A few years later (early 2000s), 10Gb Ethernet via a 10Gb/s line rate became real (as opposed to XAUI where 4 channels were used for 10Gb/s aggregate).Īnother important development was beginning - SERDES were being used more and more for chip-to-chip communication on PCBs and backplanes to replace parallel links. At this time, OC-24 (2488.32Mbps) was available and people were planning OC-192 at approximately 10Gbps. Fortunately for me, this coincided with an important time in the history of SERDES. OC-24 required a line rate above 1Gbps (1244.16 Mbps) which was supported by state-of-the-art circuits around 1990 in Bipolar and GaAs processes. During this period, the requirements for OC-1 and OC-3 were modest by today’s standards (51.84 Mbps, 155.52Mbps). In the mid 1980s, the data rate of serial links was driven in large part by telecom requirements (SONET). The SERDES area and power were secondary considerations. The reason for this is quite obvious of course – sending bytes serially rather than in parallel limits the number of cables! With one or only a few cables, maximizing the throughput over the cable was most important. SERDES have their background in communication over fiber optic and coaxial links. Reasons for serialization (Why do we need SERDES?) In this article, I’ll show examples of some of the SERDES I’ve worked on and use these examples to help explain the progress that the design and technology communities have made in the last two decades.
My career began in the late 1990s, just before the SERDES revolution. We will attempt to explain some of the underlying technology that makes serial links ubiquitous, and why that wasn’t the case 20 years go. In this two-part series, we will explore why serial links (and the SERDES that enable them) have become so popular. The last 20 years have seen an explosion in the number of serial link applications. Today, links such as PCI Express, HDMI, USB are ubiquitous.