The drive on the 'LS367 depends somewhat on whose it is. The 8T97,
according to my '78 SIGNETICS (they made them, after all) data book says it
sinks 64mA! That's quite a bit more than the 16 mA of the typcial LS367,
though Motorola claims their LS367 sinks 24 mA. It's hard to know what to
believe. That's one reason I prefer the CMOS parts, particularly the AC
from Fairchild/National, or the AHCT from Samsung. They drive at least
plenty, symmetrically at that, and the fanout is on the order ot 10^3.
Dick
----- Original Message -----
From: allisonp <allisonp_at_world.std.com>
To: <classiccmp_at_classiccmp.org>
Sent: Monday, May 22, 2000 4:22 PM
Subject: Re: Altair parts substitutions
> >> Anyway, some parts have become scarce, so I would have to use
> substitutes.
> >> For example, Jameco no longer carries the 8T97 buffer/driver. As I
recall
> >> the 8T97 is an LS373 without the inverter on the gate *and* is faster
and
> >
> >I thought that the 74LS367 and 74LS368 (the latter being the inverting
> >one) were almost direct substitutes. I think the 8Txx parts can drive a
> >heavier load, but I doubt if this will cause problems in an Altair/Imsai
>
>
> Tony is right. 8t97 and 8t98 are close to the 74LS367 and 74ls368
> in drive and exactly the same pinout.
>
> >The '373 is an octal transparent latch (with 3-state outputs) and is not
> >the same thing at all.
>
>
> the '373 wasn't available when the altair was new.
>
> >> has a higher drive current. I've heard that the MC6887 is a sub, but I
> can't
> >> find a datasheet on it.
> >>
> >> The 8101 dual-port 256bx4 RAM is no longer available, but Jameco has a
> 5101
> >> which looks like a likely sub. I would forego this type for a larger
> SRAM,
>
>
> That would work, the difference is the 5101 is cmos and the 8101 is mos.
>
> >I can't find the 8101 on any of the S100 card schematics I've looked at,
> >so I wonder what on earth it was used for.
>
>
> try 2101. the first ram card was a 256byte one using 256x4 parts if
> memeory serves.
> The denser cards were 2107/TMS4060 4kx1 Dram based.
>
> He may have meant seperate Input and output like the 2102 (1kx1).
>
> Allison
>
>
>
Received on Mon May 22 2000 - 20:42:36 BST