static sensitive PIC chips?

Hi all,

Has anyone else had problems with 16f628 chips. I am building a small project that located in another part of the house from my programmer. Both rooms are located in a carpeted basement, after making about 5 trips from programmer to target board the chip would not program anymore. I wasn't extremely careful in regards to avoiding static discharge other than grounding myself before removing the chip and again before programming it. After the first chip went defective I was much more careful, transporting the new chip in conductive foam. Even with this precaution 2 more chips are no longer responding in the programmer. Is it just me or are these chips super sensitive?

Alan

Reply to
A.P.
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There must be more to it or you got several thousand volts of static going thru you. Try wearing some antistatic strap, wear different kind of shoes, use a humidifier in the house.

If you mishandle the part you may get issues also. Don't hot plug the IC.

Reply to
Michel Catudal

What you need t do is wear polyester, maybe cotton. No wool. Use rubber soled shoes too. Those leather soled shoes generate thousands of volts, just walking around. Next take an empty spray bottle. Add some dishwashing detergent to it, and fill with water, mix up reasonably well (don't overdo it because of the suds). Then spray the carpet with the soapy water. next follow normal static discharge practices. The fact that you didn' feel a static discharge doesn't preclude one happening though. The soapy water helps a lot to cut down on static discharge, it's not perfect though.

Reply to
Earl Bollinger

Static damage is rare and fairly random. I would worry much more about the programmer and the algorithms it is using ...

Dave

Reply to
Dave Garnett

I'd prefer the use of an anti-static carpet spray, which wouldn't make the carpet as sticky as detergent would. Over time the detegerent will attract dirt and the carpet will soil faster. The ESD carpet sprays also cause some increased soiling, but it's not as bad.

A carpet in the basement makes me think it's not nylon or wool based, and is therefore may not be causing a lot of static. An increasing number of "rec room" type carpeting is now made of polyolefin. The latest olefin carpets, especially olefin/nylon mix, don't generate nearly as much static.

For my money, the static is being generated while working with the programmer, chips, and other circuitry at the desk. Some wood desktops (real wood, not photo printed melamine) generate copious amounts of static just by rubbing your hand over it. Now with winter (the air is drier despite the rain!) these sorts of things become a problem again. I like to put a small anti-static mat under my feet in my carpeted office. It cost about $50 some 10 years ago, and I never have had static problems since. (And out in my garage the floor is concrete and I have a

50's metal desk. What static?? )

-- Gordon Author: Constructing Robot Bases, Robot Builder's Sourcebook, Robot Builder's Bonanza

Reply to
Gordon McComb

What about your pc, is it grounded? I have really really mishandled my pic's ( also 16F628) and never burned one, BUT - i have burned a few pc's till i made a new grounded supply for them. If your programmer is powered from the pc it can get charged from there. An ungrounded pc _will_ get static. And if you discharge yourself and then touch the chip in the programmer, you dishcarge the hole lot throug the Pic. A defective "0" (dont know the english word - you got "phase" and "0" in your home-supply) could make it even worse. Niels

Reply to
Niels Damsgaard-Sørensen

Try to do it in the same room. You are damaging the devices with static electricity.

--Bob

Reply to
Bob Harris

Thank you all for the great advice, I will try them out.

Alan

transporting

Reply to
A.P.

It's just you(r carpet).

Seriously, if you can't remove the carpet, you should invest in a static mat and wrist strap. I have carpet in my basement, but I am very careful about grounding myself.

Reply to
Alan Holt

Hi,

I use these (and many other chips) all the time. I have seldom had one fail. Here are my 2 rules...

1) Never plug or unplug the chip with the circuit powered.

2) Keep youself grounded to the circuit with one hand while inserting or removing the chip with the other hand.

Not only with this prevent damage from static charges but also for 120 volt 'leakthru' that many devices have even when powered off.

Reply to
Luhan Monat

de-basement?

Reply to
doug

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