PLX launches USB 3.0 peripheral controllers for general purposes

Connect anything PCI Express to USB 3.0, or wise versa

ONE OF THE things that have been holding the development of USB 3.0 peripherals back to a degree, at least beyond various storage devices, have been down to lack of a what would be considered a fairly simple component, namely a peripheral controller. PLX has solved that problem by introducing a pair of USB to PCI Express peripheral controllers which should make development of USB accessories much simpler than it has been to date.

So what are we looking at here? Well, the two chips are called the USB 3380 and USB 3382 and put simply they act as an interface between the PCI Express bus and the USB 3.0 interface. PLX as a company is quite famous for its range of bridge chips like this, but this time around things are slightly different. Connect the chips in one way and they’ll go in the device that you want to add USB 3.0 connectivity to, but if you connect them the other way, you could for example connect a USB 3.0 device directly to the PCI Express bus without the need of a host controller.

The USB 3380 supports one PCI Express gen 2.0 lane while the USB 3382 supports two lanes. The interesting thing with the 3382 is that it can either support two independent PCI Express devices or the two lanes can be merged to offer additional bandwidth to whatever you want to plug in to a USB 3.0 port. PLX is suggesting two lanes of PCI Express bandwidth should work with external graphics cards, although we don’t really see this as the big seller here.

PLX block diagram PCI express to USB

Another advantage on offer here is that a wide range of ICs should work more or less out of the box with PLX’s controllers which will reduce product development time which in turn leads to lower cost. There are of course some limitations, mostly power related but at least in that case an external power brick would easily solve the problem. PLX has also included a degree of intelligence in it new peripheral controllers thanks to an integrated 8051 controller which allows the controllers to “fake” the device type to the host system. This again has been done to reduce the time it takes to develop certain solutions as the controllers will appear as standard devices of a certain type to the OS and as such no additional drivers are needed.

The peripheral controllers are comparably large chips at 10x10mm, but this is unlikely to cause a problem for the intended usage scenarios. As to how popular these solutions will be, well, we won’t really know, nor is it likely we’ll ever find out since this is one of those solutions that are needed, yet never really noticed. We can see the peripheral controllers being a helpful tool for developing various hardware solutions as well and with 400MB/s worth of bandwidth available there’s more than enough bandwidth for at least a single PCI Express lane being utilized to the max.

PLX is still awaiting USB-IF certification, although the company will start shipping samples of both solutions in Q2 with production kicking off in Q3. Estimated pricing is said to range between $7-8 in volume which should make these a pretty affordable alternative for many of the smaller hardware developers, especially those that already have PCI Express solutions in the market.S|A

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