These devices are positive-edge-triggered D-type flip-flops with a common enable input. The HCT273 devices are similar to the HCT377 devices, but feature a common clear enable (CLR)\ input instead of a latched clock.
Information at the data (D) inputs meeting the setup time requirements is transferred to the Q outputs on the positive-going edge of the clock (CLK) pulse. Clock triggering occurs at a particular voltage level and is not directly related to the positive-going pulse. When CLK is at either the high or low level, the D input has no effect at the output. The circuits are designed to prevent false clocking by transitions at (CLR)\.