Description

The Harris CD74HC123, CD74HCT123, CD74HC423 and CD74HCT423 are dual monostable multivibrators with resets. They are all retriggerable and differ only in that the 123 types can be triggered by a negative to positive reset pulse; whereas the 423 types do not have this feature. An external resistor (RX) and an external capacitor (CX) control the timing and the accuracy for the circuit. Adjustment of Rx and CX provides a wide range of output pulse widths from the Q and Q terminals. Pulse triggering on the A and B inputs occur at a particular voltage level and is not related to the rise and fall times of the trigger pulses.

Features

• Overriding Reset Terminates Output Pulse
• Triggering From the Leading or Trailing Edge
• Q and Q Buffered Outputs
• Separate Resets
• Wide Range of Output-Pulse Widths
• Schmitt Trigger on Both A and B Inputs
• 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: NIL = 30%, NIH = 30%of VCC at VCC = 5V
• HCT Types
- 4.5V to 5.5V Operation
- Direct LSTTL Input Logic Compatibility, VIL= 0.8V (Max), VIH = 2V (Min)
- CMOS Input Compatibility, Il ≤ 1µA at VOL, VOH