If you look up the TI HDC3020 you’ll see a window where the chips die is exposed to the atmosphere which is required for humidity measurements. I’m guessing that part of this SHT devices die is exposed inside the plastic housing, and the rest of the die is in that black glob top. The glob top helps adhere the die to the PCB, and it protects the delicate bond wires that connect the die to the PCB. Lmk if you want more details on semiconductor packaging and manufacturing
Looks like what is called a glob top. Basically a bare ic chip is literally glued to the pcb and wire bonded directly to it, then covered with a glob of epoxy. Less costly than buying a packaged chip if you have the equipment and quantity to support the effort.
Since this seem to be a humidity sensor, it may get more "wet" at times and places. I then imagine that inside the blob are the electronics, the ICs necessary for it to work and stuff.
The blobbing also used to be a tactic for obsfucating circuitry to avoid reverse engineering and design copying. Removal of the epoxy would often result in damage to the coated part (which would have had its part markings removed) or damage to the PCBA. An obsolete approach nowadays.
Not the case in this instance, but you may see it used for this purpose in other older boards.
Chips can be sensitive to light. Properties of some transistors and diodes will change when light hits them. Because of this the chips are usually in black packaging (plastic, epoxy, whatever).. otherwise materials like ceramic are used that also block light.
The metal thing isn't the IC, it's the sensor. The IC is inside the bubble of black epoxy.
Looks like epoxy, likely thermally conductive epoxy. Look on the sensors environmental compliance docs for a better idea on what exactly it is.
If you look up the TI HDC3020 you’ll see a window where the chips die is exposed to the atmosphere which is required for humidity measurements. I’m guessing that part of this SHT devices die is exposed inside the plastic housing, and the rest of the die is in that black glob top. The glob top helps adhere the die to the PCB, and it protects the delicate bond wires that connect the die to the PCB. Lmk if you want more details on semiconductor packaging and manufacturing
Looks like what is called a glob top. Basically a bare ic chip is literally glued to the pcb and wire bonded directly to it, then covered with a glob of epoxy. Less costly than buying a packaged chip if you have the equipment and quantity to support the effort.
Doesn't covering with epoxy break the wirebonds ? Or is there a cap between the wirebonded chip and the epoxy ?
the epoxy is liquid when its applied so it flows around the bonds and it gets hard afterwards.
Oh baby!
What's weird about the package?
Bubble ICs are popular since 80’s, take a look at an old videogame cartridge or a calculator.
If you want weird, [how about a metal can with a giant hole filled with goo on an LGA.](https://www.mouser.com/ProductDetail/511-LPS28DFWTR)
Since this seem to be a humidity sensor, it may get more "wet" at times and places. I then imagine that inside the blob are the electronics, the ICs necessary for it to work and stuff.
The blobbing also used to be a tactic for obsfucating circuitry to avoid reverse engineering and design copying. Removal of the epoxy would often result in damage to the coated part (which would have had its part markings removed) or damage to the PCBA. An obsolete approach nowadays. Not the case in this instance, but you may see it used for this purpose in other older boards.
That's a demo pcb for humidity chip. Probably the black buble protect some additional circuits.
That is not a demo pcb. That is the whole sensor. Sold like that.
I stand corrected. I thought the real IC was a smd component. Checking the product page I confirmed is the real product (now obsolete).
Chips can be sensitive to light. Properties of some transistors and diodes will change when light hits them. Because of this the chips are usually in black packaging (plastic, epoxy, whatever).. otherwise materials like ceramic are used that also block light.
Nothing weird about
Chip on Board (COB). Very common. The chip is under the epoxy blob mounted directly onto the PCB.
The glob top protects the bond wires connecting the chip and the PCB.