The ’HC374, ’HCT374, ’HC574, and ’HCT574 are octal D-type
flip-flops with 3-state outputs and the capability to drive 15
LSTTL loads. The eight edge-triggered flip-flops enter data into
their registers on the LOW to HIGH transition of clock (CP). The
output enable (OE) controls the 3-state outputs and is independent of the register operation. When OE is HIGH, the outputs are in the high-impedance state. The 374 and 574 are
identical in function and differ only in their pinout arrangements.