SN54HCT257 Overview
/ordering information NC − No internal connection The ’HCT257 devices are designed to multiplex signals from 4-bit data sources to 4-output data lines in bus-organized systems. The 3-state outputs do not load the data lines when the output-enable (OE) input is at the high logic level. To ensure the high-impedance state during power up or power down, OE should be tied to VCC through a pullup resistor;.