CD74FCT374SM

The CD74FCT374SM 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 output stage is a combination of bipolar and CMOS transistors that limits the output high level to two diode drops below VCC. This resultant lowering of output swing (0 V to 3.7 V) reduces power-bus ringing [a source of electromagnetic interference (EMI)] and minimizes VCC 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 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 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 VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

The CD74FCT374SM is characterized for operation from 0°C to 70°C.

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