On Jun 29, 2006, at 6:04 AM, Russell McMahon wrote:

>       Ye Olde TTL
> http://focus.ti.com/lit/ds/symlink/sn74ls90.pdf
>
There is another TI page (Logic selector guide?) that claims
1) the 74xx90 only exists as 7490 and 74ls90 (no HC, etc)
2) The 7490 is obsolete, but the 74ls90 is "active", and should
    still be available...
(Other vendors may vary, of course.)

I suspect that the distributer problems the OP is having stem
from distributers getting rid of the ls series entirely.

BillW
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