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flyer31
Visitor II
November 21, 2020
Question

Compatibility issues with STM32H730/STM32H723? (LQFP100)

  • November 21, 2020
  • 1 reply
  • 633 views

Hi, I just spent several hours trying to get STM32H730 Chips running in 2 of our PCBs here, also I tried one STM32H723 (LQFP100, Rev. Z). But I did NOT succeed to connect with ST-LINK to any of them (using the typical 4 wire connector with GND, SWCLK, SWDIO, NRST)... I had to solder them out again and then replace by STM32H750, and all working nicely again.

STM32H730 looks much improved concerning the electrical specs, and also the 550MHz sound nice.

Are the STM32H730 possibly much more sensitive to soldering temperatures/ soldering times? Maybe also some other Silicon class with much more narrow and temperature sensitve structures? (I must admit that I soldered them all manually with soldering iron, but I really have much exprience in doing this quite fast pin by pin, about 1-5 sec per pin ... I never had any issues with STM32F4 or STM32H7 or STM32G parts so far...).

(just these STM32H730 and STM32H723 somehow have very bad tinning - they also seem to come from another fab - they have country code TWN - the STM32H750 in our stock solder very nicely and have country code PHL).

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    flyer31Author
    Visitor II
    November 21, 2020

    Spending some further "happy hours" on this today, I came to the conclusion that we throw away all this stupid STM32H730 chips from this stupid TWN fab and send them some evil djinns ... maybe if they have some free time and Corona relaxes they should do some excursion to the STM PHL fab to learn how to do good tinning ...

    I am frightened they did chemical tinning ... we also one time by some accident ordered PCBs with chemical tinning at our PCB supplier, but such PCBs you cannot use any more really after 2-4 weeks stocked at air ... . Since this time we always take very much care that our PCBs are HAL tinned (Hot Air Laminated or so ...). I assume this is the main difference between TWN and PHL fab, but at least for manual soldering the devices this unfortunately really is crucial.

    I now repleated two times VERY careful ... making a careful "needle" side displacement test of every pin after the reflow soldering, and using abundand amounts of "nice non-clean flux" during my heat gun reflow soldering.

    After this, when connecting to power, I see that the 3V3 current is continuously 10mA (if there is any jitter in this 10mA, you can be quite sure that there are continuously power up resets coming from time to time), and that the VCAP pins 48 and 73 (connected to 2u2 caps) show 1.012 V voltage... .

    ... but anyway NO connect unfortunately ... I think somehow the needle test is not sufficient after soldering, You need som bad djinns of this stupid TWN fab presumably to esure that your chip is soldered under those crazy conditions they present to us... .

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