CY74FCT2257T

The FCT2257T has four identical two-input multiplexers that select four bits of data from two sources under the control of a common data Select input (S). The I0 inputs are selected when the Select input is LOW and the I1 inputs are selected when the Select input is HIGH. Data appears at the output in true non-inverted form for the FCT2257T. On-chip termination resistors have been added to the outputs to reduce system noise caused by reflections. The FCT2257T can be used to replace the FCT257T to reduce noise in an existing design.

The FCT2257T is a logic implementation of a four-pole,two-position switch where the position of the switch is determined by the logic levels supplied to the select input. Out-puts of FCT2257T are forced to a high-impedance "OFF" state when the Output Enable input (OE) is HIGH.|

All but FCT2257T must be in the high-impedance state to avoid currents exceeding the maximum ratings if outputs are tied together. Design of the output FCT2257T enable signals must ensure that there is no overlap when outputs of three-state devices are tied together.

The outputs of FCT2257T are designed with a power-off disable feature to allow for live insertion of boards.