Datasheet
Table Of Contents
- Chapter 1 USB251x Hub Family Differences Overview
- Chapter 2 General Description
- Chapter 3 Acronyms
- Chapter 4 Block Diagram
- Chapter 5 Pin Descriptions
- Chapter 6 LED Usage Description
- Chapter 7 Battery Charging Support
- Chapter 8 Configuration Options
- Chapter 9 DC Parameters
- 9.1 Maximum Guaranteed Ratings
- 9.2 Operating Conditions
- Figure 9.1 Supply Rise Time Model
- Table 9.1 DC Electrical Characteristics (continued)
- Table 9.2 Supply Current Unconfigured: Hi-Speed Host (ICCINTHS)
- Table 9.3 Supply Current Unconfigured: Full-Speed Host (ICCINTFS)
- Table 9.4 Supply Current Configured: Hi-Speed Host (IHCH1)
- Table 9.5 Supply Current Configured: Full-Speed Host (IFCC1)
- Table 9.6 USB251x/xi/xA/xAi Supply Current Suspend (ICSBY)
- Table 9.7 USB251xB/xBi Supply Current Suspend (ICSBY)
- Table 9.8 USB251x/xi/xA/xAi Supply Current Reset (ICRST)
- Table 9.9 USB251xB/xBi Supply Current Reset (ICRST)
- Table 9.10 Pin Capacitance for USB251x, USB251xi, USB251xA, USB251xAi
- Table 9.11 Pin Capacitance for USB251xB and USB251xBi
- 9.2.1 Package Thermal Specifications
- Chapter 10 AC Specifications
- Chapter 11 Package Outlines

USB 2.0 Hi-Speed Hub Controller
Datasheet
Revision 1.1 (04-26-10) 6 SMSC USB251x
DATASHEET
List of Figures
Figure 4.1 USB251x Hub Family Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 5.1 2-Port 36-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 5.2 3-Port 36-pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 5.3 4-Port 36-pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 5.4 3-Port 48-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 5.5 4-Port 48-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 5.6 7-Port 64-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 6.1 Dual Color LED Implementation Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 7.1 Battery Charging via External Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Figure 8.1 Block Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Figure 8.2 Block Read. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Figure 8.3 Non-Removable Pin Strap Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Figure 8.4 Pin Strap Option with IPD Pin Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Figure 8.5 LED Pin Strap Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Figure 8.6 Reset_N Timing for Default/Strap Option Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Figure 8.7 Reset_N Timing for EEPROM Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Figure 8.8 Reset_N Timing for SMBus Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Figure 9.1 Supply Rise Time Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Figure 10.1 Typical Crystal Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Figure 10.2 Formula to Find the Value of C1 and C2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Figure 10.3 Ceramic Resonator Usage with SMSC IC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Figure 11.1 36-Pin QFN, 6x6 mm Body, 0.5 mm Pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Figure 11.2 48-Pin QFN, 7x7 mm Body, 0.5 mm Pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Figure 11.3 64-Pin QFN, 9x9 mm Body, 0.5 mm Pitch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Figure 11.4 36-Pin Package Tape Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 11.5 48-Pin Package Tape Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Figure 11.6 36-Pin and 48-Pin Package Reel Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76