Heatsink for power supply chip in RPi 4B?

[Rhonda_TS]

Hi,

In all of the stuff I've read about the RPi 4B overheating, and all of the kits that I've seen with their myriad of heatsinks and fans, there is not one word mentioned about putting a heatsink on the WXL7704 power supply chip next to the power socket. It gets rather hot too. (Lower left in the images below.)



Is it just assumed to be OK when hot because it's a power supply chip and thus designed to withstand running hot?

RSVP, thanks.
RTS

[jamesh]

On the latest revision, rev1.5, the PMIC should run cooler.

[cleverca22]

there is not one word mentioned about putting a heatsink on the WXL7704 power supply chip

also, nearly every kit includes heatsinks for the ram and usb controller

but i can see in your photos, that the ram isnt showing any signs of heat, and the usb controller is just barely heating up

i think a lot of people are just blindly slapping heatsinks on things, without actually checking to see what needs it

[MikeDB]

A small 40mm 5V fan running off 3.3V will keep every component on a Pi4 cool without being noisy. Heatsinks move heat away at first but unless there's an airflow over them the air surrounding them soon reaches the same temperature and they do little.

[pidd]

There is at least one of the passive heatsink-cases that has a pillar down to that chip eg the CATURDA C2444

[trejan]

Is it just assumed to be OK when hot because it's a power supply chip and thus designed to withstand running hot?

Yes. Maximum operating temperature is 125C. It doesn't even start warning about high temperature until > 105C and will only go into thermal shutdown at 145C.

Only the heatsink that goes on the Broadcom SoC has any use. The rest of them do nothing useful and are purely cosmetic.