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gregstm
Senior II
July 25, 2026
Question

What does an STM32L452, LQFP48 package look like before it is encapsulated?

  • July 25, 2026
  • 3 replies
  • 57 views

I’m designing another PCB for the STM32L452 LQFP48, and I was wondering - how big is the die? Can I see a picture of the structure of the LQFP 48 before it is encapsulated?

I use double layer boards, and have as much ground plane under the micro, both top and bottom layer as possible. But I often sneak some power tracks around the inside perimeter of the micro. But under the plastic goo I do not know how big the die is. How far can I go with tracks before I am under the actual microprocessor? I think knowing the internal dimensions of the package would help me fine tune my printed circuit board designs.

I suppose I could destroy one to find out, but that seems like a waste (and messy). I can’t imagine it would be company confidential… or could it? If a photo is confidential, how about a CAD drawing? … or maybe an artist’s impression...

 

3 replies

MM..1
Super User
July 25, 2026

For your pcb is irelevant except you plan wire 100Amps under… Chips is around 5,3x5,3 mm and around is bonded wires to pins.

waclawek.jan
Super User
July 25, 2026

The WLCSP package will give you an idea how big the chip actually is, roughly. And the wireframe probably has a solid (possibly grounded, but maybe not) pad in the middle, to which the chip is glued.

JW

AScha.3
Super User
July 25, 2026
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gregstm
gregstmAuthor
Senior II
July 26, 2026

Thanks. Impressive (and some scary) stuff - “do not do at home” definitely applies. A very impressive microscope setup!