text.skipToContent text.skipToNavigation


Quadruple 1-of-2 Data Selectors/Multiplexers with 3-State Outputs and Series Damping Resistors


Package | PIN: DBQ | 16
Temp: I (-40 to 85)
Carrier: Cut Tape
Qty Price
1-9 $2.56
10-24 $2.31
25-99 $2.15
100-249 $1.88
250-499 $1.77
500-749 $1.50
750-999 $1.27
1000+ $1.21


  • Function and Pinout Compatible With FCT and F Logic
  • 25- Output Series Resistors to Reduce Transmission-Line Reflection Noise
  • TTL Output Level Versions of Equivalent FCT Functions
  • Edge-Rate Control Circuitry for Significantly Improved Noise Characteristics
  • Ioff Supports Partial-Power-Down Mode Operation
  • Fully Compatible With TTL Input and Output Logic Levels
  • ESD Protection Exceeds JESD 22
    • 2000-V Human-Body Model (A114-A)
    • 200-V Machine Model (A115-A)
    • 1000-V Charged-Device Model (C101)
  • 12-mA Output Sink Current
    15-mA Output Source Current
  • 3-State Outputs

Texas Instruments  CY74FCT2257ATQCT

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.