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What to connect DVDD to on STM32H7?

DanielPi
Associate II

Hello.

I am creating a board with an STM32H7R3Z8J6. I am wondering what I should connect DVDD to? My intuition and "experience" says that this is the "Digital power supply pin", but it doesn't really make sense to make that distinction on this type of component, since it "digital by default", and then you have some analog parts (which you supply through VDDA).

The "Getting started with hardware development for..." app not doesn't really specify much, it says that it's "Digital supply for the USB HS PHY". This indicates that it's a power supply and should thus be connected to the rest of the VDD net (or some other voltage). I am using USB on this board (D+ and D- connected to a USB connector), but I have connected both VDD50USB and VDD33USB to VDD (3.3V), which I got from some other spec.

There is also a diagram:

Screenshot 2024-05-30 at 06.18.52.png

where it looks like it should be connected to the VCAP net with a 100nF cap to GND.

 I also found this schematic from a Nucleo board with a similar MCU, which sort of confirms what the app note say, DVDD should be connected to the VCAP net with a 100nF cap to GND.

So how should the DVDD pin be connected?

1 ACCEPTED SOLUTION

Accepted Solutions
STOne-32
ST Employee

Dear @DanielPi DVDD.png

Yes, Indeed here an extract from the datasheet also .

Cheers,

STOne-32

View solution in original post

4 REPLIES 4
STOne-32
ST Employee

Dear @DanielPi DVDD.png

Yes, Indeed here an extract from the datasheet also .

Cheers,

STOne-32

DanielPi
Associate II

Ok so then in my case where I will be using the USB, but not use it as an OTG device, what should I do then? I will only use it as "device" (i.e. not "host").

Hi @DanielPi ,

USB_OTG is the name of our Peripheral that is generic and able to handle many USB fonctions by software: Device , Host , OTG , PD with combination of different speeds Including Internal and external PHY for High speed operations. 
So in your case , Yes , in USB device it is required as it power the digital core with 1,2V rail .

Hope it helps , STOne-32

LCE
Principal

In case of doubt - and if space allows - connect it to VCAP via 0R-resistor and add a capacitor to GND.