CD54HC257 - High Speed CMOS Logic Non-Inverting Quad 2-Input Multiplexer with 3-State Outputs

The ’HC257 and ’HCT257 are quad 2-input multiplexers which select four bits of data from two sources under the control of a common Select Input (S). The Output Enable input (OE\) is active LOW. When OE\ is HIGH, all of the outputs (1Y-4Y) are in the high impedance state regardless of all other input conditions.

Moving data from two groups of registers to four common output buses is a common use of the 257. The state of the Select input determines the particular register from which the data comes. It can also be used as a function generator.

Products containing the "CD54HC257" keyword are: CD54HC257F , CD54HC257F3A

• Buffered Inputs
• Typical Propagation Delay (In to Output) = 12ns at V_CC = 5V, C_L = 15pF, T_A = 25°C
• Fanout (Over Temperature Range)
  • Standard Outputs...10 LSTTL Loads
  • Bus Driver Outputs...15 LSTTL Loads
• Wide Operating Temperature Range...–55°C to 125°C
• Balanced Propagation Delay and Transition Times
• Significant Power Reduction Compared to LSTTL Logic ICs
• HC Types
  • 2V to 6V Operation
  • High Noise Immunity: N_IL = 30%, N_IH = 30% of V_CC at V_CC = 5V
• HCT Types
  • 4.5V to 5.5V Operation
  • Direct LSTTL Input Logic Compatibility, V_IL = 0.8V (Max), V_IH = 2V (Min)
  • CMOS Input Compatibility, I_l 1µA at V_OL, V_OH

Data sheet acquired from Harris Semiconductor