STM32H7 very hot

[jean]

Hello dear community,

I've started using STM32H743VGT6 on a custom board I've made.

I'm testing the hardware now and I quickly detected that the temperature is really high (approx. 70°c on the top of the chip package).

I have another board, based on a STM32H743BIT6, quite similar, and the temperature of this one seems normal (approx. 40°C)

• dividing the H7 clock speed by 2 really helps to reduce the temperature, but my original clock config seems right (tested with cubeMX)
• It's not easy for me to measure the current drawn by the H7, as the 3V3 is used by many other devices

Have you ever experienced that kind of issue?

Thanks a lot, have a nice day!

Jean

[jean]

Thanks for the AN5337 info! That's interesting. I've never thought about using a lower frequency. Every previous project using STM32F was running at max speed and the heat was low. Even my STM32H743 package running at 480MHz in a big package (LQFP-208) was not heating.

So indeed I might use a lower system frequency for my STM32H743 LQFP-100

I already have a wide, solid ground plane under the H7. I will also think about a place for a heat-sink.

[tawat25]

Thank you this topic i have design my board with stm32H723  i need maximum adc speed  so set clock to 550 Mhz but the chip is hot . i have down to 400 Mhz   founded temperature cool down . but adc sample rate down too. why?

[Tesla DeLorean]

Synchronous?

Check clock sources and dividers servicing the ADC.

Here we tend to unpack the RCC settings to confirm we understand the Reference Manual and what we ended up with.

[KNaim.1]

Thank a lot for this post because i have made my pcb too base on stm32h750 the mcu is very hot  at 480mhz i am going to try to reduce speed to see if any changes..  i was thinking about my design because i have put all the capacitors like intel processor on bottom layer pcb to have them close has possible from their respetive pin.

The power supply is ams1117 and its working good that deliver 3.29 volt dc and its not hot.

[Tesla DeLorean]

What kind of hot? Uncomfortable or burns to your finger hot?

The latter indicates something seriously wrong, and a conduction path you don't want. ie Internal LDO outputting 1.25V into 3.3V supply rails.

The AMS1117 can push an AMP. Might suggest you check how much your circuit is drawing vs reasonable expectations.

[KNaim.1]

Thanks DeLorean

Here is my pcb design 

It's my first stm32 pcb sure that it's not perfect because i am learning i am comming from esp32 world that is really more simple. 
I have faced some problems with clock ic  at the begining   because i have buy by mistake 3 states clock(with no data sheet Aliexpress is not perfect.but it's affordable..) and not crystal. (but achieve to make it work).
- QSPI and Spi flash are working perfect i have follow Controltech tuto on youtube  and all result was good.

- what value of resistor do you recommand for input pullup on stm32h750 pins ?