STL140N4LLF5 Overcurrent - Marking Included

[Kang1]

Currently, we have developed a USB HUB Board.

When we manufactured 5EA for the first time, it worked normally. (Current: 50mA)

When we manufactured 10EA for the second time, 5EA worked normally, and 5EA had overcurrent. (Overcurrent: 450mA)

After analyzing the difference between the two boards, we found that all parts except for one part were from the same lot, and that one part was STL140N4LLF5.

When we swapped the STL140N4LLF5 part, the FET that caused the overcurrent occurred, so the overcurrent is occurring.

I purchased the two parts from Digi-Key and Mouser, and I would like to know what the difference is.

Thank you.

[Peter BENSCH]

The two distributors mentioned have probably supplied original goods. The date code of ‘Overcurrent’ is 437, i.e. 2014 or 2024, week 37, while ‘Normal’ has the date code 040 = 2010 or 2020, week 40. It may well be that the lead frame and thus the footprint changes slightly, but this has no effect on the technical parameters.

In any case, no conclusion can be drawn from the information you have provided that one or other of the same devices will or will not work, nor why this is the case. Only with information such as the schematics can you possibly recognise where a design problem might lie.

Regards
/Peter