TIDUF35 june   2023 AM6442

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Terminology
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1  AM6442 Microprocessor
      2. 2.3.2  DP83867 gigabit Ethernet Physical Transceiver
      3. 2.3.3  DP83TD510E Single-Pair Ethernet Physical Transceiver
      4. 2.3.4  MSPM0G1107 Microcontroller
      5. 2.3.5  LMK1C1106 6-Channel Output LVCMOS 1.8-V Buffer
      6. 2.3.6  LMK6C Low-Jitter, High-Performance, Bulk-Acoustic-Wave (BAW) Fixed-Frequency LVCMOS Oscillator
      7. 2.3.7  TLVM13630 High-Density, 3-V to 36-V Input, 1-V to 6-V Output, 3-A Step-Down Power Module
      8. 2.3.8  LM74700-Q1 Reverse-Polarity Protection Ideal Diode
      9. 2.3.9  TPS62825A Synchronous Step-Down DC-DC Converter
      10. 2.3.10 LMR36006 Ultra-Small Synchronous Step-Down Converter
      11. 2.3.11 TLV62568A High-Efficiency Step-Down Buck Converter With Forced PWM
  9. 3System Design Theory
    1. 3.1 Power Subsystem
    2. 3.2 AM6442 System on Module Subsystem
    3. 3.3 Ethernet Subsystem
    4. 3.4 Power Over Data Line (PoDL) Subsystem
    5. 3.5 Additional Subsystems
      1. 3.5.1 USB 3.1 Interface
      2. 3.5.2 Micro SD Card Interface
      3. 3.5.3 SimpleLink CC3301 Wi-Fi 6 and Bluetooth Low-Energy BoosterPack Interface
      4. 3.5.4 AM6442 UART Interface
  10. 4Hardware, Software, Testing Requirements, and Test Results
    1. 4.1 Hardware Requirements
      1. 4.1.1 Board Interface
        1. 4.1.1.1 Boot Switch Configuration
        2. 4.1.1.2 Starting up the Reference Design
    2. 4.2 Software Requirements
      1. 4.2.1 PoDL PSE Protocol Programming
      2. 4.2.2 Create an SD Card Image With U-Boot and Linux
    3. 4.3 Test Setup and Procedure
  11. 5Design and Documentation Support
    1. 5.1 Design Files
      1. 5.1.1 Schematics
      2. 5.1.2 BOM
    2. 5.2 Documentation Support
    3. 5.3 Support Resources
    4. 5.4 Trademarks
  12. 6About the Author

3.1 Power Subsystem

This section gives details about the power subsystem on the reference design. Figure 3-2 shows the power tree.

GUID-20230511-SS0I-KNSG-1NS5-PXCTDHJJPDXV-low.svg Figure 3-2 Gateway Board Power Tree

The nominal input voltage of this reference design is 24 V, provided through the board main power connector. The fuse F1 protects the design from overcurrent higher than 2 A. After that, the LM74700-Q1 provides the correct applied voltage polarity, and secures reverse polarity protection. Next 24 V is provided to the DC-DC controllers to generate the required power-supply voltages.

The 6.5-V voltage supply rail is generated by the ultra-small synchronous DC-DC controller LMR36006 from the 24-V supply. The 6.5-V rail is used by the power-over data line (PoDL) subsystem.

The 5-V voltage supply rail is generated by the high-density TLVM13630 integrated power module of 24-V supply. The 5 V is used to supply the TQMa6442L system-on-module (SOM) that includes the AM6442 processor, PMIC, and DDRLP memory. In addition, the 5 V supplies additional DC-DC converters on this reference design. The rail also provides the 5-V power supply to the LaunchPad connector for the CC3301 Wi-Fi booster pack and to the TPS2553 power switch which supplies 5 V at the USB 3 connector interface.

The 3.3-V voltage supply rail is generated by the highly-accurate TPS62825 DC-DC step-down converter of the 5-V supply. The 3.3 V is used to supply various subsystems in this reference design like the DP83TD510E SPE PHYs, PoDL subsystem, and UART communication interface. Furthermore, the 3.3 V is used as input for DC-DC to generate additional voltages at the Gbit Ethernet subsystem.

The 1.8-V voltage supply rail is also generated by a second highly-accurate TPS62825 DC-DC step-down converter of the 5-V supply. The 1.8 V is used to supply various subsystems in this reference design.

The Gbit Ethernet subsystem with DP83867 Ethernet PHY requires additional accurate voltages of 2.5 V and 1.0 V. Those two voltages are generated by the highly-efficient TLV62568A step-down converter of the 3.3-V supply rail.