Figure 1. Vdd33Usb Connected To Vdd Power Supply - ST STM32H7 3 Series Application Note

Power supplies
•
When the VDD33USB pin is available, this pin can be used to supply the internal
transceiver. In this case, VDD33USB pin should receive a voltage ranging from 3.0 to
3.6 V. If VDD50USB is also available, it must be connected to VDD33USB. As an
example, when the device is powered at 1.8 V, an independent 3.3 V power supply can
be applied to VDD33USB.
When VDD33USB is connected to a separate power supply, it is independent from V
and V
following conditions must be respected (see
–
–
–
•
When neither VDD33USB nor VDD50USB is available, VDD pins are use to supply
USB transceivers and must be in the range of 3.0 to 3.6 V for the transceiver to operate
correctly.
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. It must be the last supply applied and the first supply switched OFF. The
DDA
During the power-on and power-down phases (V
V should always be lower than V
DD33USB
V rising and falling time specifications must be respected (refer to table
DD33USB
power-up/power-down operating conditions (regulator ON) and table power-
up/power-down operating conditions (regulator OFF) provided in the device
datasheets).
In operating mode, V
DD33USB
If a USB interface is used (USB OTG_HS/OTG_FS), the associated GPIOs
powered by V
DD33USB
Figure 2).
V supplies both USB OTG_HS and USB OTG_FS transceivers. If only
DD33USB
one USB transceiver is used in the application, the GPIOs associated to the other
USB transceiver are still supplied by V
If no USB interface is used (USB OTG_HS/OTG_FS), the associated GPIOs
powered by V
DD33USB
In the above two configurations, an external capacitor must be connected to
VDD33USB.
Figure 1. VDD33USB connected to V
DocID029918 Rev 1
Figure
.
DD
can be either lower or higher than V
operate between V
DD33USB_MIN
DD33USB
operate in V range (between V
DD
2):
< V minimum value),
DD DD
DD
and V
DD33USB_MAX
.
and V
DD_MIN
power supply
DD
AN4938
DD
:
(see
).
DD_MAX