Re: ECM Bench kelp needed

[thergen@svn.net]

Bruce,

Try:
http://www.digikey.com/scripts/US/DKSUS.dll?Detail?Ref=100075&Row=46625
which is a 74ls161 (digikey part search on 74ls161).

The 74S161 is in the Schottky TTL family - faster, uses more power, inputs
require more current.  It would probably work.

The 74HC161 is in the High Speed CMOS family - wider power supply range,
low power, *different input threshold than regular TTL*.  The inputs may
not be driven reliably by TTL or certain eproms like a 2732 (check the Voh
spec on the eprom output and the Vih spec on the 74HC161 input).

Don't use the HC part.

The HCT family is more compatible than HC with the various flavors of TTL.

Hope that helps,
Tom


On Thu, 13 Jan 2000, Bruce Plecan wrote:

> I have a wiring diagram for my DIS signal generator that uses two 74LS161s.
> I have been every where locally and no one has them.   I have found some
> similiar part nos. at Digi-Key,  those being a:
> DM74S161-ND,   and a
> MM74HC161N-MM
> Can I use these?, one perferable to the other?, what's the difference in the
> three.
> Thanks
> Grumpy
>