Why does it seem so much harder to find a 74hct238 chip than the
It's not *impossible* to find, but I'm curious if there is some reason why, and if I should be looking at another solution to my problem instead.
Thanks, Daniel.
TTL devices historically tended to have low-active enables and strobes due to the lower impedance of the low state. The 3-8 decoders with low-active outputs are therefore more common.
Because active low enables are so much more common that active high ones and there is a reason for that.
Chip enable inputs are usually active-low.
Cheers
Phil Hobbs
Later devices often never had the same success as the earlier set, and certainly in places where hobbyists might buy things, often the selection is limited, and hence the earlier devices are what they carry.
So even though later devices might be better than earlier ones, you'd still see projects using 7490 decade counters (or some later logic type variation), while the 74390 which was a dual device and for many applicatins worked fine, was ignored. Remember, a lot of people have early databooks that dont' cover the later devices.
Michael
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