PLX Technology was showing off three new PCI Express switch products at Bus and Board, including the PLX ExpressLane PEX 8525 (Fig. 1), PEX 8533 (Fig. 2), and PEX 8547 (Fig. 3).
The PLX ExpressLane PEX 8525 (24 lanes, 5 ports) is a multipurpose, non-blocking switch. It is similar to the PEX 8524, but the PEX 8525 lacks non-transparency support, and only 3 ports support the hot-plug feature. Latency is reduced to 110ns-115ns by using a cut-thru architecture similar to that found on Ethernet switches. This allows an incoming packet to be forwarded out the proper port before it is completely received.
This feature is also found in the other two new devices. The PEX 8533 (32 lanes, 6 ports) has similar characteristics to the PEX 8525. These reduced features make the chips less expensive and forego features that are generally unused in most instances. Designers needing the full capabilities can use existing PLX PCI Express switch chips.
Similarly, the PEX 8547 (48 lanes, 3 ports) is designed to work with a pair of x16 PCI Express devices, typically graphics cards. The switch is less flexible than the recently released PEX 8548 (48 lanes, 9 ports), but again, the reduced functionality reduces costs — and power requirements, to 110 mW/lane.
All are available in lead-free packaging. Pricing for the PEX 8525 is $35, for the PEX 8533 is $45, and for the PEX 8547 is $55. For more information, visit PLX Technology.