VAX9000 unearthed
Jon Elson
elson at pico-systems.com
Sat Feb 19 12:28:21 CST 2022
On 2/18/22 21:43, ben via cctalk wrote:
>
> The 70's was all low scale tech. I suspect it was the high
> speed/edge rates more the power that kept ECL from common
> use. Any other views on this topic. Ben, who only had
> access to RADIO SHACK in the 70's.
> PS: Still grumbling about buying life time tubes at a big
> price,
> just to see all tubes discontinued a year or two later.
Edge rates on pedestrian MECL 10K were not crazy fast. Rise
and fall of about 1 ns, but the gate propagation delay was
ALSO about 1 ns, so that was a lot faster than TTL. ECL was
very easy to work with, crosstalk was not a common issue.
But, you HAD to terminate any line over a foot, and better
to make it 6" to be sure. And, the termination and pulldown
resistors ate a LOT of power!
Jon
More information about the cctalk
mailing list