Description
These devices are positive edge triggered flip-flops. The difference between HD74HCT564 and HD74HCT574 is only that the former has inverting outputs and the latter has noninvertering outputs.
Data at the D inputs, meeting the set-up and hold time requirements, are transferred to the Q or Q outputs on positive going transitions of the clock (CK) input. when a high logic level is applied to the output control (OC) input, all outputs go to a high impedance state, regardless of what signals are present at the other inputs and the state of the storage elements.

FEATUREs
• LSTTL Output Logic Level Compatibility as well as CMOS Output Compatibility
• High Speed Operation: tpd (D to Q, Q) = 15 ns typ (CL = 50 pF)
• High Output Current: Fanout of 15 LSTTL Loads
• Wide Operating Voltage: VCC = 4.5 to 5.5 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)