STM32H750XBH6 BGA soldering

[SJaha.2]

Hi there.

I got in trouble with H750XBH6.

I designed a costum board base on mcu above.

I followed datasheet recommendations for BGA footprint.

Now I got problem with soldering. The pads are too small and doesn't make connection with chip balls.

So the chip doesn't work properly and I guess there are many of non-connected pins specially on GND and VCC pins under chip.

I got confused about the 0.225mm pad recommendation in datasheet.

Why the pads are smaller than the chip balls?

The balls are about 0.4mm ​

[FBL]

Hi @SJaha.2​,

The spherical shape makes the pads smaller than the diameter of the balls which is compliant with JEDEC standards.