The eight flip-flops of the ’AC374 devices are D-type edge-triggered flip-flops. On the positive transition of the clock (CLK) input, the Q outputs are set to the logic levels set up at the data (D) inputs.

A buffered output-enable (OE) input can be used to place the eight outputs in either a normal logic state (high or low logic levels) or the high-impedance state. In the high-impedance state, the outputs neither load nor drive the bus lines significantly. The high-impedance state and the increased drive provide the capability to drive bus lines in bus-organized systems without need for interface or pullup components.

OE does not affect internal operations of the flip-flop. Old data can be retained or new data can be entered while the outputs are in the high-impedance state.

The RCA-CD54/74AC374 and CD54/74AC534 and the CD54/74ACT374 and CD54/74ACT534 octal D-type, 3-state, positive-edge triggered flip-flops use the RCA ADVANCED CMOS technology. The eight flip-flops enter data into their registers on the LOW-to-HIGH transition of the clock (CP). The Output Enable (OE) controls the 3-state outputs and is independent of the register operation. When the Output Enable (OE) is HIGH, the outputs are in the high-impedance state. The CD54/74AC/ACT374 and CD54/74AC/ACT534 share the same pin configurations, but the CD54/74AC/ACT374 outputs are non-inverted while the CD54/74AC/ACT534 devices have inverted outputs. (For flow-through pin configurations, see CD54/74AC/ACT564 and CD54/74AC/ACT574.)

The CD74AC/ACT374 and CD74AC/ACT534 are supplied in 20-lead dual-in-line plastic packages (E suffix) and in 20-lead dual-in-line small-outline plastic packages (M suffix). Both package types are operable over the following temperature ranges: Commercial (0 to 70°C); Industrial (-40 to +85°C); and Extended Industrial/Military (-55 to +125°C).

The CD54AC/ACT374 and CD54AC/ACT534, available in chip form (H suffix), are operable over the -55 to +125°C temperature range.