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Sci.Electronics.Basics -> D82C55AC-2
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Author: aleksaDate: 15:06 20-05-08
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I've bought 10 pcs of "82C55" through mail, and received D82C55AC-2.
The problem is that the output high voltage of any pin is not 5V, but
3.8V.
Nothing is connected to the port pins, VCC is 4.85V.
Am I wrong thinking that CMOS chips should have far more than 3.8V on
output pins?
Thanks
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Author: Paul E. SchoenDate: 18:59 20-05-08
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"aleksa" <aleksaZR@gmail.com> wrote in message
news:018b7590-87fb-4a29-ba87-1871db7a6c24@w34g2000prm.googlegroups.com...
> I've bought 10 pcs of "82C55" through mail, and received D82C55AC-2.
>
> The problem is that the output high voltage of any pin is not 5V, but
> 3.8V.
>
> Nothing is connected to the port pins, VCC is 4.85V.
>
> Am I wrong thinking that CMOS chips should have far more than 3.8V on
> output pins?
>
> Thanks
I have an old product that used an 8255 to interface to TTL logic, and I
recall some problems when we tried to use CMOS versions. I think we could
fix it by using pullups, but it was easier to get the non-CMOS version. I
don't have the data sheets handy, but I think your parts probably meet
specs. I think the 8255s are actually BICMOS.
Paul
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Author: JeffMDate: 20:06 20-05-08
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