CY74FCT257T - Quadruple 1-of-2 Data Selectors/Multiplexers with 3-State Outputs

The CY74FCT257T 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 at the output is noninverted.

The CY74FCT257T is a logic implementation of a four-pole, two-position switch, where the position of the switch is determined by the logic levels at S. Outputs are in the high-impedance state when the output-enable (OE\) input is high.

All but one device must be in the high-impedance state to avoid currents exceeding the maximum ratings if outputs are tied together. OE\ inputs 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 I_off. The I_off circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.

Products containing the "CY74FCT257T" keyword are: CY74FCT257TQC , CY74FCT257TQCT , CY74FCT257TQCT

• Function, Pinout, and Drive Compatible With FCT and F Logic
• Reduced V_OH (Typically = 3.3 V) Version of Equivalent FCT Functions
• Edge-Rate Control Circuitry for Significantly Improved Noise Characteristics
• I_off Supports Partial-Power-Down Mode Operation
• Matched Rise and Fall Times
• 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)
• 64-mA Output Sink Current
  32-mA Output Source Current
• 3-State Outputs