STM32L412K8 Exposed Pad question

[EngPete]

Hi!

I'm an EE designing a PCB. Referencing the datasheet: https://www.st.com/resource/en/datasheet/stm32l412k8.pdf

Section 7.4 on page 178, UFQFPN48, the Exposed Pad (EP) says that it should be connected to GND.

Section 7.6 on page 184, UFQFPN32 (the chip that I'm using) the EP function isn't mentioned. Should I connect this to GND or leave it floating?

My gut instinct is to connect it to GND, though has anyone had any experience with EPs and the ST standard way of dealing with them?

Thank you for any assistance in advance.

Pete.

[STOne-32 · Accepted solution]

Dear @EngPete ,

Welcome in our STCommunity,  it is generally recommended to connect the Exposed Pad (EP) to the ground (GND) for better EMC properties and power dissipation. This applies to the UFQFPN32 package of the STM32L412K8 as well.

However, it's important to note that the EP is not always connected to VSS internally, especially in smaller packages like the UFQFPN32.

Hope it helps you.

STOne-32

[EngPete]

@STOne-32,

Thank you for your response. My training has always led me to connect the EP to GND (unless stated otherwise), though I found it strange that the datasheet didn't specify it for this processor, and did for others in the same datasheet.

I'll connect the EP to GND now.

Thank you again!

Pete.

[Andrew Neil]

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@EngPete wrote:

strange that the datasheet didn't specify it for this processor, and did for others in the same datasheet.

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Indeed - it does seem like an omission from the datasheet.

Hopefully the datasheet can be updated to be consistent/complete ...