CD74FCT374

The CD74FCT374 is an octal, edge-triggered, D-type flip-flop that uses a small-geometry BiCMOS technology and features 3-state outputs designed specifically for driving highly capacitive or relatively low-impedance loads. This device is particularly suitable for implementing buffer registers, I/O ports, bidirectional bus drivers, and working registers.

The CD74FCT374 output stage is a combination of bipolar and CMOS transistors that limits the output high level to two diode drops below V_CC. This CD74FCT374 resultant lowering of output swing (0 V to 3.7 V) reduces power-bus ringing [a source of electromagnetic interference (EMI)] and minimizes V_CC bounce and ground bounce and their effects during simultaneous output switching. The output configuration also enhances switching speed and is capable of sinking 48 mA.

The CD74FCT374 eight flip-flops enter data into their registers on the low-to-high transition of the clock (CLK). The output-enable (OE) input controls the 3-state outputs and is independent of the register operation. When OE is high, the outputs are in the high-impedance state.

A buffered OE input can be used to place the eight outputs in either a normal logic state (high or low) or the high-impedance state. In the high-impedance state, the outputs neither load nor drive the bus lines significantly. The CD74FCT374 high-impedance state and the increased drive provide the capability to drive bus lines without 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.

To ensure the high-impedance state during power up or power down, OE should be tied to V_CC through a pullup resistor; the CD74FCT374 minimum value of the resistor is determined by the current-sinking capability of the driver.

The CD74FCT374 is characterized for operation from 0°C to 70°C.