Beyond the 48ns Barrier: How Semtech and Microchip Reimagined USB Extension for Pro AV and Industrial Systems
USB’s distance limitation has never been about signal strength—it’s about protocol timing. Semtech’s UEX series, powered by Microchip’s SmartFusion®2 SoC FPGAs, fundamentally redefines USB 2.0 extension by solving the architectural constraints of the protocol layer—not just amplifying signals.
You Already Know You Need USB Extension. The Question Is: How?
As the demand for USB connectivity in professional AV, medical and industrial systems grows, so does the need for reliable, standards-compliant USB extension. While the USB specification limits cable length to 5 meters, the real obstacle isn’t electrical—it’s timing.
The Protocol Reality: Why Simple Extension Fails
At the heart of USB’s distance limitation is the protocol’s strict timeouts. For USB2.0 high-speed mode, if a host command isn’t acknowledged by the device within 23-bit times, the transaction fails—even if the signal is perfectly intact. In other words, if the device does not answer the host packet within ~48ns, roughly a few meters of propagation delay, it will be considered broken. Conventional extenders like repeater cables or hub chains try to stretch this limit, but only manage incremental gains, often compromising compliance and reliability.
For example, daisy-chaining five hubs and maximum-length cables yield a mere 280ps of timing margin. Even in best-case scenarios, that only adds a few extra centimeters—hardly worth the added complexity.
Traditional Approaches, Predictable Limitations
- Hub Chaining: Limited to five tiers, introduces latency, power distribution challenges and multiple failure points
- Repeater Cables: Amplify signals without addressing protocol compliance, leading to unreliable performance
- USB-over-Cat5: Often require drivers, lack transparency or function as proxies instead of true USB extenders
Semtech's UEX Series: A Protocol-Centric Breakthrough
Semtech’s UEX2000 USB 2.0 extenders fundamentally redefine USB extension by operating at the protocol layer, not just the physical layer. This enables real USB transactions to traverse standard IP networks—without violating specification timing.
Intelligent Protocol Processing
The UEX platform intelligently manages USB transactions:
- Transaction Management: Maintains timing compliance over long distances
- Error Recovery: Detects and resolves protocol-level faults in real time
- Flow Control: Optimized IP-based discovery provides consistent responsiveness
Network-Native Architecture
By extending USB over Ethernet, UEX transforms USB extension into a scalable, manageable network feature:
- Point-to-point or switch-based deployment
- Firmware updates and monitoring over the network
- Graphical USB device tree visualization and diagnostics
Built-In Security and Control
- Device Class Filtering: Block unauthorized device types at the hardware level
- Tier Violation Protection: Alerts prevent spec violations
- Access Control: Policy-based device authorization
Operational Advantages
- Plug-and-Play: No drivers needed—works across Windows, macOS, Linux and ChromeOS
- Real-Time Monitoring: USB health metrics and logs
- Remote Diagnostics: Troubleshoot without onsite access
The Competitive Advantage: Protocol, Not Propagation
Traditional extenders attempt to overcome distance. UEX redefines the architecture. By handling USB transactions at the protocol level, UEX unlocks new capabilities—without compromising performance or security.
Inside the UEX Platform—Powered by the Microchip SmartFusion® 2 SoC FPGA
Semtech’s innovation in USB protocol handling is made possible by Microchip’s SmartFusion®2 SoC FPGAs, a uniquely integrated platform combining low-power FPGA fabric and an ARM® Cortex®-M3 processor.
This architecture allows Semtech to build a fully programmable USB stack with deterministic control, real-time monitoring and system-level fault management—all in a compact, energy-efficient design.
Inside the UEX System
The Semtech UEX2000 extenders reference design integrates key components from Microchip's portfolio:
- SmartFusion2 SoC FPGA (M2S010) – Protocol control and system management
- USB3340 PHY – USB 2.0 compliant physical layer
- LAN8830 PHY – Ethernet connectivity
- LAN7800 (optional) – USB 3.1 expansion for future readiness
Figure 1—Semtech UEX Reference Design takes a Microchip Total Systems Solution Approach
The SmartFusion 2 SoC is factory pre-programmed, offering high-volume deploy ability and plug-and-play performance. The entire solution operates seamlessly without external software drivers.
Designed for Scalability
The UEX2000 functions in standalone mode or integrates with Semtech’s BlueRiver® AV Manager, providing full USB monitoring and control. The UEX2000 is suitable for:
- AV conferencing and BYOM environments
- Factory floor device control
- Medical operating rooms and imaging systems
With Microchip’s system-level support and long product lifecycle commitment, Semtech's UEX series is both deployable today and adaptable for tomorrow.
Engineering USB Extension for the Next Decade
The collaboration between Semtech and Microchip demonstrates what’s possible when innovation focuses on architectural challenges, not just physical limitations. UEX isn’t just a USB extender—it’s a network-native platform engineered for reliability, security and control.
Ready to move beyond USB's limits? Learn more at:
- Semtech's USB Extension web page
- Our SmartFusion 2 FPGAs web page