Best way to toast TTL

[Steve Stutman]

Awhile back, perhaps early '80s, there was a paper or monograph from 
Tektronix which discussed affects of ESD on TTL. Many people believe(d) 
that ESD can damage or destroy MOS parts, but that there is no effect on 
TTL parts.

The above publication claimed differently. Stated that although ESD does 
not destroy TTL function, immunty to noise and (IIRC) switching speeds 
are impacted because of damage to gate structures.

Steve






Grant Stockly wrote:

> Before I write to the group, Kurt Klemm, if you read this please try 
> sending me a message on my web forum at http://www.stockly.com  I am 
> getting your e-mails but based on them it sounds like you are not 
> getting mine!  : (
>
> ---  Now to the rest:
>
> I'm wishing I've kept all the broken TTL chips over the years...
>
> I am evaluating a TOP2004 programmer for testing TTL chips.  I bought 
> it off of ebay from 
> http://www.mcumall.com/comersus/store/comersus_dynamicIndex.asp  I 
> bought it on ebay because the price was cheaper.  They are located in 
> Canada and it took 5 days to get shipped to Alaska.  Very well 
> packed.  The other TOP programmers ship from china/japan.
>
> I want to be able to recommend a TTL tester to my customers of the 
> Kenbak kit.  With 132 74xx TTL chips it would really come in handy!
>
> So far I think it does a good job.  If I lift a signal leg on a 74LS04 
> it both can't auto detect anything and will report a 7404 as bad.  I 
> only have one known bad part, a 74LS376.  It DID report it as bad and 
> undetectable.
>
> What I'm wondering is if anyone knows how I can prematurely kill a TTL 
> device or simulate static failure.  I'd like to try to test how 
> thoroughly the programmer tests the chips.  It can't tell the 
> difference between a 7410 and 7412, but that isn't too important for 
> knowing the chip works (mostly)
>
> On a second note, I have successfully over clocked my Kenbak 500%.  
> Its running happily at 5MHz.  : )  Although it gets a lot hotter!  I 
> need heat sinks...
>
> --I suppose giving one 12v to simulate hooking up a power supply wrong?
> --Hooking 12v to a device normally powered at 5v?
> --Shorting out a buffer output?  (I think some buffers are designed to 
> be shorted out though)
> --Vehicle ignition coil to an input?  : D
>
> Grant
>