Thanks for all the info, Brent! The MECL II MC1022 is an edge-triggered D flip-flop using master-slave design. I'll have to look up the others you mentioned, especially the National DM8510 and Sprague NE8828.
I've previously overlooked the MC778 mW RTL D flip-flop, which also uses a variant of the three-SR design. However, it is a cruder device than the MC3060 and SN7474, in that its asynchronous preset and clear only work when the clock input is high, whereas they work at any time in the MC3060 and SN7474. I haven't analyzed the circuit, but I'm guessing that they simply didn't gate the preset and clear inputs into the master flip-flop of the MC778, but only into the slave FF. Best regards, Eric
