On September 2, the USB Promoter Group announced the USB4 Version 2.0 standard, which enables data transfers of up to 80 Gbps (10GB/s) over USB Type-C cables.
According to Angstronomics, USB4 Version 2.0 may support PAM3 (Pulse Amplitude Modulation) data encoding and bring asymmetric transmission of up to 120Gbps.
The USB Type-C interface was standardized in 2014 and features 2 pairs of high-speed data links, each with transmit and receives capabilities. Therefore, in a normal USB data configuration, the 4 channels are configured in a 2 Tx + 2 Rx symmetric setting. USB4 Version 2.0 reaches 40 Gbps per channel, resulting in a bi-directional bandwidth of 80 Gbps.
In April of this year, information about USB4 Version 2.0 (PAM3) was listed on the Yestech website as being “for USB with next-generation PAM3 modulation”.
If true, USB4 Version 2.0 will support asymmetric 3 Tx + 1 Rx configurations, meaning 120 Gbps output from the host and 40 Gbps return from the device to the host, making it useful in many scenarios where asymmetric data transfer is required, such as display + docking station, 80 Gbps for display output and 40 Gbps for data transfer.
Angstronomics also says that Intel has taken the lead in adapting and that Meteor Lake processors are expected to support USB4 Version 2.0.
According to an announcement from the USB Promoter Group, the specifications for USB Type-C and USB PD will also be updated to achieve higher levels of data performance. All of these specification updates are expected to be released in advance of this year’s USB DevDays series of developer events scheduled for November.
In addition, the USB Promoter Group will also be working on protocol updates to enable higher performance USB 3.2, DisplayPort (DP) and PCI Express (PCIe) performance.
Key highlights of the USB4 Version 2.0 standard are as follows.
Up to 80 Gbps operation, based on a new physical layer architecture using existing 40 Gbps USB Type-C passive cables and newly defined 80 Gbps USB Type-C active cables.
Updated data and display protocols to better take advantage of the increase in available bandwidth.
USB data architecture updates now enable USB 3.2 data tunneling beyond 20 Gbps.
Updates to DisplayPort and PCIe standards to comply with the latest specifications.
Backward compatible with USB4 Version 1.0, USB 3.2, USB 2.0, and Thunderbolt 3 standards.
