Agilent English 2014-03-03 PDF 1.52 MB 5991-1148EN c20140829 [12] free download

File name English _ 2014-03-03 _ PDF 1.52 MB 5991-1148EN c20140829 [12].pdf

Keysight Technologies Characterizing Hi-Speed USB 2.0 Serial Buses In Embedded Designs Application Note Introduction The hi-speed USB 2.0 serial bus is used today in a broad range of computer as well as embedded designs. One good example of an embedded design is the oscilloscope itself, which often includes USB interfaces for connectivity, mouse operation, and external data storage. Most other types of electronic products, such as medical equipment or industrial control systems, include USB interfaces as well. The USB 2.0 serial interface has been rapidly replacing older RS-232 serial interfaces in embedded designs. Although USB-IF physical layer compliance certification is typically required by computer OEMs for suppliers of USB devices and silicon chip-sets, compliance certification is typically not a requirement for embedded products. Nonetheless, R&D testing and verification of physical layer characteristics of embedded designs with integrated USB interfaces is extremely important to ensure reliable operation of end-products. Simply selecting USB components, integrating them into an embedded design, and then hoping that everything functions is not good enough. Even if the system appears to function, how much margin does it have? Or how does it perform under various environmental conditions such as temperature or humidity? When debugging and verifying the performance of hi-speed USB 2.0 designs, the Keysight Technologies, Inc. InfiniiVision 4000 and 6000 X-Series oscilloscopes offer several advantages over many higher performance oscilloscopes that are typically used for full compliance testing. One obvious advantage is the lower price of the 4000 and 6000 X-Series oscilloscopes. But the advantages of the scope go beyond just price. Although many higher performance Windows-based scopes have been optimized for advanced waveform analysis, Keysight's InfiniiVision 4000 and 6000 X-Series oscilloscopes have been optimized for signal visualization and debug. This application note begins with a discussion of probing the hi-speed USB 2.0 serial bus using Keysight's N2750A InfiniiMode Series differential active probe. We then show some of the unique debugging tools and capabilities of the Keysight 4000 and 6000 X-Series portable bench-top scopes that can help you get your embedded designs to market faster. 03 | Keysight | Characterizing Hi-Speed USB 2.0 Serial Buses In Embedded Designs - Data Sheet Probing the hi-speed USB 2.0 differential bus Since the hi-speed USB 2.0 bus is differential, a differential active probe must be used to capture and analyze signals. Keysight recommends using the N2750A InfiniiMode Series of differential active probes shown in Figure 1. This family of differential active probes comes in three different bandwidth models ranging from 1