STM32 High Speed USB
A number of the STM32F4xx devices are equipped with two USB ports, one FS (Full Speed) and one HS (High Speed). The HS port has a built-in FS PHY, but to achieve HS, an external PHY is necessary.
Enabling USB HS port in Stm32CubeMX reveals the pinpout:
To save a crystal, the STM32F4xx can be driven by a 24 MHz crystal, which is then outputted on MCO1:
Store bought USB3300 breakout
To test the HS PHY I managed to find a Chinese breakout board:
With this board I managed to verify it working, but the USB Mini-B connector was/is annoying.