Confused by datasheet for the STM32L082KZT6 - no VDD_USB pin??

[Neal Radford]

Posted on June 08, 2018 at 10:26

Hi All,

I am brought a a bunch of STM32L082KZT6

(STM32L082 in LPFP32 pinout) 

parts and I've started designing my PCB but in the datasheet the VDD_USB pin is omitted (only) for this package BUT ST says it supports USB device mode.

I have looked at the part using STM32CubeMX and enabling USB shows USB_DP(PA12) and USB_DM(PA11) but no VDD_USB pin...

Can I assume it just gets USB_VDD power from VDD and I should just make sure VDD is >= 3V if I am using USB?

Any and all help greatly appreciated!

Cheers,

Neal

#stm32l082kz-vdd_usb

[Neal Radford]

Posted on June 08, 2018 at 11:14

I found an anwser in the forum for a similar part here:

'Hi Robert,

Indeed,for the devices were VDD_USB pin is not available, the USB transceiver and the two associated pads (PA11 and PA12) are powered by VDD;

You may refer to the

/external-link.jspa?url=http%3A%2F%2Fwww.st.com%2Fcontent%2Fccc%2Fresource%2Ftechnical%2Fdocument%2Fdatasheet%2Fdc%2Fd6%2F6d%2F24%2F86%2F2a%2F40%2Fd3%2FDM00108pdf%2Ffiles%2FDM00108pdf%2Fjcr%3Acontent%2Ftranslations%2Fen.DM00108pdf

relevantto your device (table 79) to have more information about the USB electrical characterstics thar you should respect.

Khouloud.

https://community.st.com/0D50X00009XkXv4SAF 

'

[Khouloud GARSI · Accepted solution]

Posted on June 08, 2018 at 11:44

Hi

raddybaby

‌,

For some devices, when in high pin count packages, feature a dedicated VDDUSB pin, while, when assembled in low pin count packages(your case LQFP32), have only the VDD pin to ensure the USB functionality.

For more details, please refer to section 'Power' in application note

https://community.st.com/0D50X00009XkVtDSAV

'USB hardware and PCB guidelines using STM32 MCUs'.

Khouloud.

[Neal Radford]

Posted on June 08, 2018 at 12:12

Hi Khouloud,

Many thanks for your prompt and accurate answer! :)

Cheers,

Neal

[Khouloud GARSI]

Posted on June 08, 2018 at 14:09

Hi Neal,

You're welcome  

Regards,

Khouloud.