SPRADO3B December 2024 – September 2025 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP
USB0 interface supports DFU (Device Firmware Upgrade) boot. When the USB0 is configured for DFU boot, permanent 3.3V supply (direct or using divider) is not recommended to be connected to the USB0_VBUS input. Connecting a permanent supply equivalent to the USB0_VBUS divider input is not allowed. Connecting supply without the USB VBUS Detect Voltage Divider / Clamp Circuit violates fail-safe operation.
A 5V supply from the host (switched) connected through the USB interface connector is recommended to be connected to USB0_VBUS input through resistor divider, as per the processor-specific data sheet recommendations. Zener diode can be removed and the two resistors (16.5kΩ and 3.48kΩ) can be combined into a single 20kΩ resistor for the USB VBUS Detect Voltage Divider / Clamp Circuit if the custom board design does not apply a VBUS potential > 5.5V, and on-board supply is connected.