External switching power supply support still planned for STM32L4?

[mhaun]

Posted on April 18, 2017 at 20:28

AN4621 'STM32L4 ultra-low-power features overview' says (page 16):

The STM32L4A6xG, thanks to the external SMPS supply option, makes it possible to force on the Vcore pins (when the MR is in use) an external VDD12 supply. When VDD12 is forced by an external source and is higher than the output of the internal LDO, the current is taken from this external supply and the overall power efficiency is significantly improved when using an external step down DC/DC converter.

I just checked the STM32L4A6xG datasheet, and none of the packages show a VDD12 pin.  So, simple question I guess: What happened to external SMPS support?  Was it cut from the product?

[Uwe Bonnes]

Posted on April 18, 2017 at 23:37

The STM32L496xx datasheet know about a P option. Look on page 75 and '8 Part numbering'. However distributor availabilty is not (yet?) given.

[mhaun]

Posted on April 18, 2017 at 23:50

Fascinating.  So the STM32L4A6xx datasheet does not have this (the P option in the part-numbering table), even though AN4621 claims that the VDD12 pin is *only* available on the STM32L4A6 devices, and not on any others!  It would appear that app note is just plain wrong, because I discovered a more recent app note, AN4978, which lists the applicable products as

STM32L452RE, STM32L476ZG, STM32L496RG, STM32L496AG, STM32L496ZG, STM32L496VE, STM32L433RC

Sigh.  ST, would you please prioritize your documentation?  And get some people who can write, while you're at it...

[Nesrine M_O]

Posted on April 19, 2017 at 11:42

Hi

Haun.Mark

,

We confirm the issue related to the

AN4621 and it will be fixed in coming release of the document.

Thank you for bringing this issue to our attention and Sorry for the inconvenience it may bring.

-Nesrine-