74系列逻辑芯片/74LVC244APW
The 74LVC244A; 74LVCH244A is an octal non-inverting buffer/line driver with 3-state outputs. The 3-state outputs are controlled by the output enable inputs 1OEand 2OE. A HIGH on nOEcauses the outputs to assumea high-impedance OFF-state. Schmitt-trigger action at all inputs makes the circuit highly tolerant for slower input rise and fall times. Inputs can be driven from either 3.3 V or 5.0 Vdevices. In 3-state operation, outputs can handle 5 V. These features allow the use of these devices as translators in a mixed 3.3 V and 5 V environment. The 74LVCH244A bus hold on data inputs eliminates the need for external pull-up resistors to hold unused inputs.