CY74FCT2257T中文资料具有三态输出和串联阻尼电阻的四路 2 选 1 数据选择器/多路复用器数据手册TI规格书

描述 Description

The CY74FCT2257T has four identical two-input multiplexers that select four bits of data from two sources under the control of a common data-select (S) input. The I0 inputs are selected when S is low, and the I1 inputs are selected when S is high. Data appears at the output in noninverted form for the CY74FCT2257T. On-chip termination resistors at the outputs reduce system noise caused by reflections. The CY74FCT2257T can replace the FCT257T to reduce noise in an existing design. The CY74FCT2257T is a logic implementation of a four-pole, two-position switch, in which the position of the switch is determined by the logic levels supplied to S. Outputs are forced to the high-impedance off state when the output-enable (OE\\) input is high. All but one device must be in the high-impedance state to prevent currents from exceeding the maximum ratings if outputs are tied together. Design of the OE\\ signals must ensure that there is no overlap when outputs of 3-state devices are tied together. This device is fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.

特性 Features

• Function and Pinout Compatible With FCT and F Logic
• TTL Output Level Versions of Equivalent FCT Functions
• Ioff Supports Partial-Power-Down Mode Operation
• ESD Protection Exceeds JESD 22
• 200-V Machine Model (A115-A)
• 12-mA Output Sink Current 15-mA Output Source Current
• 3-State Outputs