USB4 – No more Mr. Nice Guy, your USB-C connector has to do it all! – #38

EEs Talk Tech - An Electrical Engineering Podcast
USB4 - No more Mr. Nice Guy, your USB-C connector has to do it all! - #38

New tunneling modes, the scoop on plugfests, and 40 Gbps!

Get the FREE! Tech Tip eBook about testing 6 emerging technolgy standards:

Subscribe on YouTube ►

It feels like USB 3.2 just came out, but USB4 is HERE! With USB4, gone are the days of wondering what’s behind that USB Type-C connector – all the functionality is mandatory. And, you get double the speed! 40 Gbps over two 20 Gpbs lines keeps Moore’s law happy (which makes us happy).

Find out more in today’s podcast with Jit Lim, Mike Hoffman, and Daniel Bogdanoff.

Video version:

Twitter: @DanielBogdanoff:

Subscribe with your podcast tool:






Notes & Topics:

The USB-IF released the USB4 Spec in September
USB4 requires that you use the USB Type C connector
USB4 is fully backwards compatible
USB4 uses a 20 Gbps x2 link (pronounced “by two”) so Moore’s law still holds (yay!)
USB 3.2 took 10 Gbps and doubled it to 20 Gbps

It’s USB4 not USB 4.0 and not USB 4 (confirmed)

With USB4 you must implement USB-PD (USB Power Delivery), but in the past it was optional.
USB4 brings a doubling bitrates, you must use Type C connector, and must be backwards compatible all the way to USB2

USB 3 and USB 3.2 had a lot of alternate modes, but USB4 implements a tunneling mode. With tunneling allows you to send packets of USB, DisplayPort, or PCIe inside of the USB protocol. This means you don’t have to run it as an alternate mode, which requires extra silicon.

The silicon is often prototyped before a spec is actually released, so that the spec can match reality and be possible to build.

USB4 is already being prototyped and tested. At the USB workshop-plugfest
USB plugfests are very secret, and company names aren’t used. They use a “test ID number” instead of company name, and the attendance is very limited. In many cases, only Keysight and the company testing their device are allowed to be in the room while the testing is done.

A “Compliance Test Spec” describes how you test a device against a specification. Because, you can’t test for every single thing in the spec, but you can test a subset of things to verify performance.

Will USB take over everything? It depends on the other organizations and specifications groups. There are other ecosystems and organizations like VESA (DisplayPort) and HDMI that are autonomous. But, both HDMI and VESA have a USB Type-C mode that allows the protocols to work over a USB Type C connector

USB4 implementation is very complex! The different speeds that could be used are pretty complex. USB4 is advertised 40 Gbps, but it’s actually 20 Gbps x2.

It can be 5 Gbps, 10 Gbps, 20 Gbps, and run at x1 or x2, and it can also do alt modes.

Are there any main competitors to USB4? What about the lightning connector from Apple?

There’s evidence that there will be a USB4 native display, and some high end USB4 monitors already exist.

USB4 is coming, and if you want to be on the leading edge you better get started now (and why)!

38:20 – stupid questions:
When will see USB5? What’s the lamest way someone could use USB4?
If USB4 is truly universal, shouldn’t it go into space?

Helpful Links:

Keysight Bench Facebook page:

Keysight RF Facebook page:

EEs Talk Tech Electrical Engineering podcast:

Check out our blog:

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.