Best way to toast TTL

[Steve Stutman]

Should have been "effects of ESD on TTL"; prdn.



Steve Stutman wrote:

> 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
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> 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
>>
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