SLLS413L February   2000  – June 2017 TUSB2046B , TUSB2046I


  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      USB-Tiered Configuration Example
  4. Revision History
  5. Description (Continued)
  6. Pin Configuration and Functions
    1.     Pin Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Differential Driver Switching Characteristics (Full Speed Mode)
    7. 7.7 Differential Driver Switching Characteristics (Low Speed Mode)
    8. 7.8 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 USB Power Management
      2. 8.3.2 Clock Generation
    4. 8.4 Device Functional Modes
      1. 8.4.1 Vendor ID and Product ID With External Serial EEPROM
    5. 8.5 Programming
      1. Table 1. EEPROM Memory Map
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
    1. 10.1 TUSB2046x Power Supply
    2. 10.2 Downstream Port Power
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Placement
      2. 11.1.2 Differential Pairs
      3. 11.1.3 Ground
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Related Links
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information




An SGS Thompson M93C46 EEPROM, or equivalent, stores the programmable VID and PID. When the EEPROM interface is enabled (EXTMEM = 0), the EECLK and EEDATA are internally pulled down (100 μA) inside the TUSB2046x. The internal pulldowns are disabled when the EEPROM interface is disabled (EXTMEM = 1).

The EEPROM is programmed with the three 16-bit locations as shown in Table 1. Connecting terminal 6 of the EEPROM high (ORG = 1) organizes the EEPROM memory into 64×16-bit words.

Table 1. EEPROM Memory Map

ADDRESS D15 D14 D13 D12–D8 D7–D0
00000 0 GANGED 00000 00000 00000000
00001 VID high-byte VID low-byte
00010 PID high-byte PID low-byte

The D and Q signals of the EEPROM must be tied together using a 1-kΩ resistor with the common I/O operations forming a single-wire bus. After system power-on reset, the TUSB2046x performs a one-time access read operation from the EEPROM if the EXTMEM terminal is pulled low and the chip select(s) of the EEPROM is connected to the system power-on reset. Initially, the EEDATA terminal is driven by the TUSB2046x to send a start bit (1) which is followed by the read instruction (10) and the starting-word address (00000). Once the read instruction is received, the instruction and address are decoded by the EEPROM, which then sends the data to the output shift register. At this point, the hub stops driving the EEDATA terminal and the EEPROM starts driving. A dummy (0) bit is then output and the first three 16-bit words in the EEPROM are output with the most significant bit (MSB) first.

The output data changes are triggered by the rising edge of the clock provided by the TUSB2046x on the EECLK terminal. The SGS-Thompson M936C46 EEPROM is recommended because it advances to the next memory location by automatically incrementing the address internally. Any EEPROM used must have the automatic internal address advance function. After reading the three words of data from the EEPROM, the TUSB2046x puts the EEPROM interface into a high-impedance condition (pulled down internally) to allow other logic to share the EEPROM. The EEPROM read operation is summarized in Figure 9. For more details on EEPROM operation, refer to SGS-Thompson Microelectronics M93C46 Serial Microwire Bus EEPROM data sheet.

TUSB2046B TUSB2046I eeprom_lls413.gifFigure 9. EEPROM Read Operation Timing Diagram