CD74HCT157

Features:

• Common Select Inputs
• Separate Enable Inputs
• Buffered inputs and Outputs
• Fanout (Over Temperature Range)
- Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL Loads
- Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads
• Wide Operating Temperature Range . . . -55oC to 125oC
• 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  1mA at V_OL, V_OH



Pinout




Specifications

DC Supply Voltage, V_CC . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 7V
DC Input Diode Current, I_IK
For V_I < -0.5V or V_I > V_CC + 0.5V . . . . . . . . . . . . . . . . . . . .±20mA
DC Output Diode Current, IOK
For V_O < -0.5V or V_O > V_CC + 0.5V . . . . . . . . . . . . . . . . . . .±20mA
DC Output Source or Sink Current per Output Pin, I_O
For V_O > -0.5V or V_O < V_CC + 0.5V . . . . . . . . . . . . . . . . . . .±25mA
DC V_CC or Ground Current, I_CC or IGND . . . . . . . . . . . . . . . ±50mA



Description

   The Harris CD74HC157, CD74HCT157, CD74HC158 and CD74HCT158 are quad 2-input multiplexers which select four bits of data from two sources under the control of a common Select input (S). The Enable input (E ) is active Low. When (E ) is High, all of the outputs in the 158, the inverting type, (1Y -4Y ) are forced High and in the 157, the noninverting type, all of the outputs (1Y -4Y ) are forced Low, regardless of all other input conditions.

   Moving data from two groups of registers to four common output busses is a common use of CD74HCT157. The state of the Select input determines the particular register from which the data comes. They can also be used as function generators.