The \x92FCT157T devices are quad two-input multiplexers that select four bits of data from two sources under the control of a common data-select (S) input. The output-enable (E\) input is active low. When E\ is high, all of the outputs (Y) are forced low, regardless of all other input conditions.

Moving data from two groups of registers to four common output buses is a common use of the \x92FCT157T devices. The state of S determines the particular register from which the data comes. It also can be used as a function generator. These devices are useful for implementing highly irregular logic by generating any 4 of the 16 different functions of 2 variables, with 1 variable common.

The \x92FCT157T devices are logic implementations of a four-pole, two-position switch, where the position of the switch is determined by the logic levels at S.

These devices are 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.

• Function, Pinout, and Drive Compatible With FCT and F Logic
• Reduced VOH (Typically = 3.3 V) Versions of Equivalent FCT Functions
• Edge-Rate Control Circuitry for Significantly Improved Noise Characteristics
• Ioff 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)
• CY54FCT157T
  • 32-mA Output Sink Current
  • 12-mA Output Source Current
• CY74FCT157T
  • 64-mA Output Sink Current
  • 32-mA Output Source Current
• 3-State Outputs