CompactPCI Serial - The Next Generation CompactPCI

3M Ultra Hard Metric (UHM) Connector - The next generation 2mm Hard Metric System

2009-04-27, R. Nuiten, T. Remhof

Using modern high speed serial bus protocols, many System design engineers are looking for a boost in system performance. 2mm hard-metric connector based designs have historically been unable to maximize performance and signal integrity due to severe crosstalk occurring at speeds greater than 1 Gbps.

3M's new Ultra Hard Metric Connector is the industry's first fully-shielded, lowest crosstalk 2mm Hard Metric connector. It can improve and enable the performance of 2mm Hard Metric systems without costly backplane redesigns or forklift upgrades.

The UHM socket connector is designed to be intermateable to 2mm hard-metric (IEC 61076-4-101) headers and compatible with 2mm hard metric PCB footprints. It therefore helps enable much greater performance in legacy backplane designs. As a result, standard Compact PCI and VME 64x systems can support a high density multi-gigabit, high-speed serial IO protocols such as SAS, SATA, Rapid IO, PCI Express® and Gigabit Ethernet.

3M UHM Connector

The patented "virtual coaxial box" shielding technology from 3M dramatically reduces the severe crosstalk commonly experienced at 1- to 1.5-Gbps speeds, allowing the new Ultra Hard Metric (UHM) socket connector from 3M to achieve speeds greater than 7 Gbps even when mated with standard unshielded 2mm hard-metric headers.

3M shielding technology reduces crosstalk

The "virtual coaxial box" provides a matched impedance signal path and gives the designer the freedom to drive 100 Ohm differential signal pairs in both columns and rows. This provides maximum signal density and performance, but also maintains compatibility to common column-differential pair configurations found in legacy HM-systems and cable applications.

As an example, the crosstalk is evaluated for a HM-HM mated pair and HM-UHM mated pair with 2 neighbouring aggressor pairs. In the tested environment, even at 7Gb/s, the UHM maintains its excellent shielding properties and reduces crosstalk significantly.

Increased noise at 7Gb/s

UHM decreased noise at 7Gb/s

The modular design of the UHM socket connector from 3M also gives system design engineers the flexibility to design the right level of signal integrity while satisfying required mechanical constraints. Five-row (A, B, CL, CR, AB) and eight- row (D, E, DE, FL, FR) form factors are available for high signal density. In addition, the socket supports 100 ohm differential pairs in rows or columns.

The new UHM socket connector from 3M is ideal for backplane applications using 2mm hard-metric connector technology that require higher signal speeds combined with higher signal densities, such as VME bus (VME 64x) and CompactPCI® backplane applications including test and measurement (PXI™), process control, military, enterprise computing, telecommunications and factory automation.

Roland Nuiten, Tilo Remhof, 3M Deutschland GmbH

3M Ultra Hard Metric (UHM) Connector - The next generation 2mm Hard Metric System

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