The CD74FCT244 and CD74FCT244AT are octal buffer/line drivers with 3-state outputs using a small-geometry BiCMOS technology. The output stages are a combination of bipolar and CMOS transistors that limit the output high level to two diode drops below VCC. This resultant lowering of output swing (0 V to 3.7 V) reduces the 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 64 mA.
These devices are organized as two 4-bit buffers/line drivers with separate active-low output-enable (OE\) inputs. When OE\ is low, the device passes data from the A inputs to the Y outputs. When OE\ is high, 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.
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