High Speed with Signal Integrity eBook

IMPROVING SI PERFORMANCE

WITH PADDLE CARD TECHNOLOGY FOR MICRO-COAXIAL CABLE HARNESSES HIROKI MASHIMA, PRODUCT MARKETING, I-PEX

Infrastructure telecommunication equipment, such as servers and switches, has become increasingly faster in the enterprise market. Therefore, signal integrity (SI) performance must be improved for each component used in these systems. Improvement of SI performance has a role in improving equipment performance. The challenge is that conventional PCB trace transmission has large insertion losses with limited transmission distance. Jumper harnesses that use cables to solve these problems are attracting attention as a possible solution. Figure 1 shows the conventional PCB trace transmission from ASIC to I/O. Figure 2 shows the jumper harness transmission from ASIC to I/O,

instead of PCB tracing as in Figure 1. This solution can reduce transmission loss by minimizing the PCB trace length using a low-profile connector, which can be placed under the heat sink (closer to ASIC), and with a directly terminated cable to an I/O connector. THE CHALLENGE The premise is that the transmission loss must be improved while lowering the connector height. The reason for lowering the connector size is that the connector needs to be placed under the heat sink to bring it closer to the ASIC (as shown in Fig. 2) to reduce transmission loss. Transmission speed is assumed to be 56 Gb/s PAM4 (frequency 14 GHz).

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