On Monday, May 28, 2012 01:45:40 PM Jon Elson did opine: > gene heskett wrote: > > But there are still plenty of the older TTL stuffs gathering dust on > > the shelves at Newark et all. The advantage of CMOS is to me, the > > much larger noise immunity. Running on 5 volt rails, noise has to be > > nearly half that 5 volts in order to even get into the active regions > > of the logic. TTL only needs about .6 volts of noise to get into the > > active area if the total swing, which running on 5 volts is from .1 > > volts for a zero, and about 3.1 volts for a logic 1 when loaded to > > its rated fanout. Typical guaranteed logic zero might extend as high > > as .6 volts, and logic 1 is guaranteed only for inputs above 2.4 > > volts. > > Yes, in some cases a pull-up resistor can help greatly with noise > immunity. But, I sure hope I never order something from Newark and get > a 30-year old part! > > Jon > Unless of course you are looking for a 30 year old part. ;)
In the past, I've probably been shipped 5 to 10 year old semi's but they were always as good a new. Except for old old pmos stuff that can fail from the purple plague, I have never had a problem. Those I watch for, and see if I can find a compatible nmos or cmos workalike for. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> Marvelous! The super-user's going to boot me! What a finely tuned response to the situation! ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
