DEC bus transceivers

On 10/24/2016 04:30 PM, Paul Koning wrote: For the QBUS from the PDP11 Bus Handbook 1979, page 125: AC Specifications Bus driver output pin capacitive load: Not to exceed 10 pF Propagation delay: Not to exceed 35 ns Skew (difference in propagation time between slowest and fastest gate): Not to exceed 25 ns Rise/Fall Times: Transition time from 10% to 90% for positive transition, and from 90% to 10% for negative transition, must be no faster than 10 ns and no slower than 1 us It's faster than the Unibus (that Guy posted) presumably because QBUS systems tend to be much smaller but a driver that meets the Unibus spec is good on the QBUS too. On the receiver, maybe the way to go would be a linear comparator. It would be easy enough to come up with a 1.5V rail (half way between the 1.3V low and 1.7V high levels) running down the length. And you have to look but you can find them with a fast enough propagation speed. The only thing I'm not seeing is meeting the 10pF capacitive load; the spec sheets just don't say. Dave