Intel Thunderbolt Ups the I/O Ante
By Bob Hult, Bishop & Associates Inc.

The race to faster connection links, both internal and external, have driven the connector industry to develop entirely new products that have bumped their rated bandwidth from a few hundred megahertz to 25+ Gb/s. The introduction of the universal serial bus (USB) 3.0 caused some skeptics to question the practical value of 5 Gb/s I/O links, as so few applications could take advantage of that data rate. USB 3.0 is now appearing on a host of computers and peripherals, which enable them to support new generations of emerging high-speed applications.

In September 2009, Intel demonstrated their LightPeak technology, a high-speed optic interface that would initially be rated at 10 Gb/s, but could conceivably be increased as demand for higher data rates developed. Little additional news about LightPeak surfaced until February 24, 2011, when Apple Computer introduced several new MacBook Pro notebooks that sported a new copper 10 Gb/s I/O port.

The interface, dubbed Thunderbolt, apparently grew out of the LightPeak project. Thunderbolt offers some unique characteristics that may impact connectivity in a wide range of electronic products. Using a slightly modified Mini-DisplayPort 20-position connector, each Thunderbolt interface will feature: 

• Two 10 Gb/s full-duplex channels

• Isochronous protocol to ensure time critical data delivery

• No new software required

• Power consumption of about one watt

• Support multiple devices arranged in a daisy-chain topology

• Integrated power to enable remote devices

• Plug compatibility with existing DisplayPort interfaces

• Thunderbolt cable assemblies can support multiple devices

• The initial Thunderbolt interface uses a slightly modified copper Mini DisplayPort connector, but a fiber optic alternative is waiting in the wings when higher speed or longer reach will be required.

Intel reported that a Thunderbolt interface could transfer a full-length, high-definition movie in about 30 seconds.

Intel sees Thunderbolt as an alternative to application-specific cables such as HDMI, as it is capable of supporting a variety of devices with a common interface, thus simplifying the interconnection process. The mini-DisplayPort connector allows laptops and tablet computers to be designed with thinner profiles. The same cable could provide links between a home media server, external storage, large flat panel TVs, high-end audio, and security systems.

Thunderbolt represents a close collaboration between Intel and Apple Computer. The chosen mini-DisplayPort connector was originally developed by Apple and has been certified by the VESA trade organization. One could look at Thunderbolt as an IEEE 1394 (FireWire) interface on steroids. Initially, Apple will be providing Thunderbolt cable assemblies.

The first product to sport a Thunderbolt interface will be on an Apple notebook. This makes sense, as the typical Apple devotee is often an early adopter of new technology, and willing to pay a premium for the newest and coolest products.

Since the initial announcement, several suppliers of peripheral equipment, including monitors, high-end storage, HD video cameras, and business equipment have indicated their intent to include a Thunderbolt interface.

Not everyone is happy with the introduction of Thunderbolt into the I/O arena. Concerns have been raised about Intel’s lack of aggressive support of USB 3.0. Does it make sense to introduce another interface when USB 3.0 will satisfy the vast majority of current and anticipated applications? Rather than simplify the selection of I/O, the addition of Thunderbolt may end up crowding the space-constrained I/O panel, especially in thin laptops or other portable devices.

Cost is another issue, with 10 Gb/s, Thunderbolt is likely to command a price premium above the 5 Gb/s USB 3.0.

It is unclear if and how Thunderbolt will impact the continuing evolution of USB, as well as HDMI. Both of these interfaces currently enjoy extensive penetration of the market, and have demonstrated an ongoing commitment to upgrading performance, as required.

Given the technical and marketing power of Intel and Apple, this technology will be well worth watching.

Bishop & Associates Comments: 

• The introduction of Thunderbolt technology represents the next step in high-speed I/O interfaces.

• Thunderbolt is a good example of how advances in chip technology has enabled existing copper connectors and cables to perform at speeds much higher than originally specified.

• The initial 10 Gb/s iteration using a copper interface includes a roadmap to a fiber-optic alternative that could support much higher speeds and cable assembly lengths.

• It is unclear if the initial implementation in select Apple computers indicates any shared intellectual property with them, or if Intel has total control.

• Broad adoption of Thunderbolt among mass-market personal computer and peripheral manufacturers will depend on user demand and willingness to pay a price premium.

• It is possible that Thunderbolt may be ahead of its time, and at least in the short term, may serve a relatively small high-end niche market.