USB4 Specification Announced, Based on Thunderbolt, Supports Up to 40Gbps

The USB Promoter Group today announced the pending release of the USB4 specification, a major update to deliver the next generation USB architecture.

USB4 is based on the Thunderbolt protocol recently contributed by Intel. It doubles the bandwidth of USB and enables multiple simultaneous data and display protocols.

The new USB4 architecture defines a method to share a single high-speed link with multiple end device types dynamically that best serves the transfer of data by type and application. As the USB Type-CTM connector has evolved into the role as the external display port of many host products, the USB4 specification provides the host the ability to optimally scale allocations for display data flow. Even as the USB4 specification introduces a new underlying protocol, compatibility with existing USB 3.2, USB 2.0 and Thunderbolt 3 hosts and devices is supported; the resulting connection scales to the best mutual capability of the devices being connected.


“The primary goal of USB is to deliver the best user experience combining data, display and power delivery over a user-friendly and robust cable and connector solution,” said Brad Saunders, USB Promoter Group Chairman. “The USB4 solution specifically tailors bus operation to further enhance this experience by optimizing the blend of data and display over a single connection and enabling the further doubling of performance.”

Key characteristics of the USB4 solution include:
● Two-lane operation using existing USB Type-C cables and up to 40 Gbps operation over 40 Gbps-
certified cables
● Multiple data and display protocols to efficiently share the total available bandwidth over the
bus
● Backward compatibility with USB 3.2, USB 2.0 and Thunderbolt 3

The draft specification for USB4 is in the final stages of review with over 50 companies participating. It will be published around the middle of 2019 alongside an updated USB Type-C specification for USB4 bus discovery, configuration and performance requirements.

The USB Promoter Group consists of Apple, HP, Intel, Microsoft, Renesas, ST Microelectronics, and Texas Instruments.