Part Number: BQ40Z50-R2
Hello,
The BQ40Z50-R2 is used on a battery pack 3S-1P 3.6Vx3 3500mA (prototype phase).
When the battery pack is soldered on the PCB supporting the BQ40Z50-R2, the BQ40Z50-R2 is dammaged at each time.
Dammages consequences are never the same. Sometime, it's not possible to write on the component register. Sometime, one register can not be read, it is never the same register.
In first, we hase suspected ESD dammage. Our process is strict, and although this component is very sensitive, this track is excluded.
In second, we hase suspected an overheat during battery soldering. The BQ40Z50-R2 is far from the solder area; this track is excluded.
All the following connecting orders results to dammage :
- GND in first, then the VPACK, then the VC1,2,3,
- GND in first, then the VC1,2,3, then the VPACK
There is a third curious ascertainment : when the battery pack is connected using a connector (no solder), there is no dommage.
The solder matérial is ESD and qualified for our process. It can not be the responsible? The max esd voltage measured is lower than 20V.
We would like to have some help for understanding.
Do you have some idea about the possible root cause?
Other informations :
The electrical diagram is like on the datasheet (p28/51),
The programming is such that the swtich Q2 is closed once VPACK appears.
regards,
Arnaud M.