DESCRIPTION:
The FCT157T, FCT257T/FCT2257T are high-speed quad 2-input multiplexers built using an advanced dual metal CMOS technology. Four bits of data from two sources can be selected using the common select input. The four buffered outputs present the selected data in the true (non-inverting) form.
The FCT157T has a common, active-LOW, enable input. When the enable input is not active, all four outputs are held LOW. A common application of ‘FCT157T is to move data from two different groups of registers to a common bus. Another application is as a function generator. The ‘FCT157T can generate any four of the 16 different functions of two variables with one variable common.
The FCT257T/FCT2257T have a common Output Enable (OE) input. When OE is HIGH, all outputs are switched to a high-impedance state allowing the outputs to interface directly with bus-oriented systems.
The FCT2257T has balanced output drive with current limiting resistors. This offers low ground bounce, minimal undershoot and controlled output fall times-reducing the need for external series terminating resistors. FCT2xxxT parts are plug-in replacements for FCTxxxT parts.

FEATURES:
• Common features:
   – Low input and output leakage ≤1µA (max.)
   – CMOS power levels
   – True TTL input and output compatibility
      – VOH = 3.3V (typ.)
      – VOL = 0.3V (typ.)
   – Meets or exceeds JEDEC standard 18 specifications
   – Product available in Radiation Tolerant and Radiation Enhanced versions
   – Military product compliant to MIL-STD-883, Class B and DESC listed (dual marked)
   – Available in DIP, SOIC, SSOP, QSOP, CERPACK and LCC packages
• Features for FCT157T/257T:
   – Std., A, C and D speed grades
   – High drive outputs (-15mA IOH, 48mA IOL)
• Features for FCT2257T:
   – Std., A, and C speed grades
   – Resistor outputs (-15mA IOH, 12mA IOL Com.) (-12mA IOH, 12mA IOL Mil.)
   – Reduced system switching noise