Electronic – Reverse engineer: How to remove the black plastic that hides the ics

integrated-circuitpcbreverse-engineering

I am hacking a circuit and it has this black plastic thing (see picture below) that hides part of the circuit.

enter image description here

How can I remove them to see what is inside?

What they are for? I think they are for chips that have no packaging, is this right?

What the real name of this?

Thanks for your help.

Best Answer

This is known as Chip-On-Board (COB) technology, the black material is epoxy resin, it is the same as the black material on ICs. Note than the bonding wires encased in the resin are very thin and fragile. COB technology is sometimes used to prevent reverse engineering.

This YouTube video demonstrates a process for removing the resin packaging on ICs using a hotplate, nitric acid, acetone, and a rotary tool.

This video YouTube video demonstrates a simpler (but more destructive) method for removing the resin from a COB, using just a heat-gun and a hobby knife. This method destroys the bonding wires.

And here's a related question, with more information about COBs: What kind of components are black blobs on a PCB?

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Electronic – How to remove the buzzer from this PCB whose solder side is inaccessible

You could quieten the buzzer by filling the hole in the top of the plastic. If you pour in something rubbery (hot glue could be good) then it would almost certainly muffle the sound.

To remove it, I'd crack the plastic with some pliers removing enough to heat the legs with a soldering iron.

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For the question of the different numbers between the chips they are probably the date codes / lot number that many manufacturers use to track when and where a part was made. When customers report failures that can be useful to isolate manufacturing problems down to particular factories or batches.

I couldn't find documentation for the DS1307 in particular but here's an example for another Maxim DS series part:

Clarification of DS1804 Ordering Information and Package Marking

For that part the final two lines are:

yywwrr
###xx

Where:

yy = Last 2 digits of year of assembly
ww = Work week of assembly
rr = Die revision code
### = Last 3 digits of lot number
xx = Up to 2 alpha characters of lot number suffix

Best Answer

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