[time-nuts] HP8568B firware eproms anyone ?

Didier Juges didier at cox.net
Thu Oct 19 20:33:44 EDT 2006

Many CMOS chips draw higher supply current with floating inputs, as the 
internal buffers may bias themselves in the middle of the range, where 
both transistors are turned on. That may lead to increased temperature 
and failure over time. In many cases, floating inputs will simply toggle 
as a function of whatever signal line is nearby through stray capacitance.

I also support tying them to something...


Poul-Henning Kamp wrote:
> In message <PKEGJHPHLLBACEOICCBJIEMBIJAA.jmiles at pop.net>, "John Miles" writes:
>> Heh, that's great.  Interesting that at least some CMOS parts will work.  I
>> may have had some bad chips, but the same ones that failed in an 8566B
>> worked fine in a 494AP.
>> Not knowing what happens if an address line toggles in the middle of a read
>> cycle, I wonder if it'd be a good idea to tie those floating address lines
>> to ground or Vcc...
> Yeah, I will probably do that next time I have it open.

More information about the time-nuts mailing list