Can a 14 Pin PIC be Cut to 8 Pin?

[AtomSoft]

Ok Cool, you are right though also. If the chip fails you may never know why... besides it being half a chip

 

[nickelflippr]

I like the idea of a Frankenstein PIC, seeing how that the poster wants to play a gag on his friends. I would approach it a little differently by digging out a cavity on the bottom of a DIP package and dead bugging a sot2-3 PIC10f in that. Then a little kynar or magnet wire hookups to the DIP pins. That way you could make the 14 pin device look really nasty by sanding, or etching off the top to expose the silicon, cutting off ends, and otherwise roughing it up.

 

[Mr RB]

You could just grind the ends off the chip and remove as many pins as you like provided you leave all the ICSP and power pins.

 

[PICMICRO]

Its not impossible to cut a IC and still use it:
**broken link removed**

Also most DIE are in center of IC. You could always make a adapter to turn the 14 pin device into a 8 pin dip as a better choice.

Thanks for the straight answer.
So, its possible.
Dear Nay-Sayers and ridiculators, listen again, its not impossible.

 

[Electroenthusiast]

Its not impossible to cut a IC and still use it:
**broken link removed**

Also most DIE are in center of IC. You could always make a adapter to turn the 14 pin device into a 8 pin dip as a better choice.

I didn't understand how he powers the IC. If most of the die remains at the centre then why the make ICs big?

 

[jpanhalt]

I didn't understand how he powers the IC. If most of the die remains at the centre then why the make ICs big?

The IC has to be big so there is room for the legs.

Chip on board (COB) or chip on glass (COG) avoid that need. Other technologies are reducing size requirements for chips with external connections, but they are increasingly harder to solder manually.

John

 

[OlPhart]

Howdy, not to put too fine a point on it... why not open up your hard drive, have a friendly 10 second look, then "reseal" it. See how that works for ya.... entire concept is patently absurd <<<)))

 

[DerStrom8]

I didn't understand how he powers the IC. If most of the die remains at the centre then why the make ICs big?

Standard pin spacing is 1/10th of an inch, so in order to space the pins properly, the chips must be made large.

 

[Electroenthusiast]

The IC has to be big so there is room for the legs.

Chip on board (COB) or chip on glass (COG) avoid that need. Other technologies are reducing size requirements for chips with external connections, but they are increasingly harder to solder manually.
John

So, its just to facilitate soldering manually.

Standard pin spacing is 1/10th of an inch, so in order to space the pins properly, the chips must be made large.

Why not change that standard?

 

[neophyl]

So, its just to facilitate soldering manually.


Why not change that standard?

They have, its called surface mount.

 

[dr peppers]

The chip sits on a die in the centre of the package, if you cut away either side of the centre and you dont cut any needed internal lead outs to the pins you have left then it might just work, the danger is that you might bend over or mangle some of the disconnected pin lead outs and short them decking the supply or something, if you try it check the ends with a magnifier and make sure theres no shorts.

I have done exactly this, not so long back, only mine was for diffo reasons, I had some boards with pic18f series chips on them, they were scrap but before they were placed in the secure disposal bin here at work the devices were removed and I found some others in my scrap box, I think they were special function video chips, they were cut down with a grinder and inserted, you couldnt tell, and I won some nice 18f pics.

 

[Dreak]

you certainly cannot chop it off unless you own a hi-fi lab

 

[Electroenthusiast]

They have, its called surface mount.

I see ... may i have the datasheet/IC number of any equivalent ic? like those equivalent to basic 74*** series .

 

[neophyl]

I see ... may i have the datasheet/IC number of any equivalent ic? like those equivalent to basic 74*** series .

The vast majority of parts come in a surface mount package these days, any web search for a package followed by smt as a keyword should turn up a supplier. How about a 74ls00 as an example for you, I put that into google and the first result for me was https://octopart.com/sn74ls00d-texas%2Binstruments-26121

While I wouldnt buy from them personally (im in the UK so would look at Rapid, CPC/Farnell etc first) it illustrates the point. If space is at a premium in a board design then using surface mount is the way to go as thats what it was designed for.

Chopping up chips is an interesting experiment and as the OP and others have shown can work but for creating reproducible and reliable designs then using the 'proper' parts is much better and essential for non hobby/interest use.

 

[secretagent]

I don't think its possible to cut a PIC up because the most valuable parts are in the center it propbably is possible if you cut the last 1/4 off one side... why dont you just straight up try it?

Just a guess though i dont want to try it with anything i have...

 

[trash]

Ok... what drugs are you people on and where do I get some ?

Yes, I'm trying not to ridicule this thread because I know some people are trying to ask a sensible question even if it seems ridiculous from a technical point of view.

Ok... the first thing is cutting a chip up is going to break it.
There is just no way around it. It doesn't matter if you only need a couple of pins and the rest might be just taking up space.
The chip's pins form part of it's structure and any modification runs the risk of damaging the fine gold wires, the chip itself which is very brittle or shorting other pins with copper filings etc.

Even if you were extremely careful to reduce the casing with acetone and other chemicals, there is lots of risk for very little reward in general applications.
So if somebody put the challenge to me, I would be confident that I could make it work and I'm sure there are many others who can too.
So lets say you're going to try it anyway. How many chips do you think you might destroy before you can get one to work and work reliably ?

The simplest solutions are the best.
The first is to use an SMD PIC. they're usually about 1/5th the size of their conventional DIL cousins. They're designed to be small and more suited to your application.

If you have a 14 pin PIC and you only need 4 pins, then you might consider using a simpler chip.
If for example you were using a 16F877 a 10F200 might be a much better chip. Of course internal processing, memory and functions might be a consideration and a more complex chip selected for the task.
Another option jumps to mind and that is to cut up a smart card like a silver or gold card for the task. They're quite tolerant of abuse like that.

 

[secretagent]

Trash, Remember assumptions are always wrong... You are assuming that it is impossible to cut a chips end off... But It can be done as it has been proven already... I don't think that trying to be unhelpful in a thread does anyone good... We want usefull information not negative comments...

 

[trash]

yes. You are correct.
I won't say it's impossible, just improbable that most people will be able to make it work

I should make my point of view clear; By all means, for the purpose of education, R&D or just dumb luck. Go for it !
Getting your hands dirty is the best way to learn anything.
I'm the kind of person who would cut up a chip just to prove it can be done.

In this example I just think SMD or another PIC is the better example.

I didn't notice which chip we were talking about cutting up other than it was a PIC.
http://www.interfacebus.com/IC-package-cut-away-view.jpg

 

[dr peppers]

I remember something maybe on another forum, but some geyser used a shaping machine to shave the lid off a pic to get to the fuses with a uv source so that he could re-blow the code protection and read/copy the device.

I cant remember if the guy suceeded or not, but I understand microchip have now altered the design and put a shield over the fuses so someone probably did it.

 

[trash]

hehehe.... that wasn't my work I had other "simpler" methods for bypassing the security on PICs.

I wrote an article a while ago "How to Skin a fox", about physically disassembling our local cable TV smart cards.
Unfortunately it has been lost in a server crash many years ago. It's amusing what can be accomplished with acetone, an ultrasonic cleaner and a HeCd laser.
Even the old photos are stuck on a crashed hard drive I have been meaning to recover.

There are plenty of other people who have done the same things and taken it further. There's a couple of good videos on youtube etc.