TIDUF35 june 2023 AM6442
This section gives details about the power subsystem on the reference design. Figure 3-2 shows the 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.