74HCT123 Series
High Speed CMOS Logic Dual Retriggerable Monostable Multivibrators with Reset
Manufacturer: Texas Instruments
Link to Manufacturer Page: https://www.ti.com/
Catalog
High Speed CMOS Logic Dual Retriggerable Monostable Multivibrators with Reset
| Part | Independent Circuits | Voltage - Supply [Max] | Voltage - Supply [Min] | Mounting Type | Logic Type | Schmitt Trigger Input | Supplier Device Package | Operating Temperature [Min] | Operating Temperature [Max] | Current - Output High, Low | Propagation Delay | Package / Case | Package / Case |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Texas Instruments CD74HCT123E | 2 | 5.5 V | 4.5 V | Through Hole | Monostable | 16-PDIP | -55 °C | 125 °C | 4 mA, 4 mA | 25 ns | 0.3 in, 7.62 mm | 16-DIP | |
Texas Instruments CD74HCT123MT | 2 | 5.5 V | 4.5 V | Surface Mount | Monostable | 16-SOIC | -55 °C | 125 °C | 4 mA, 4 mA | 25 ns | 0.154 in, 3.9 mm Width | 16-SOIC | |
Texas Instruments CD74HCT123ME4 | 2 | 5.5 V | 4.5 V | Surface Mount | Monostable | 16-SOIC | -55 °C | 125 °C | 4 mA, 4 mA | 25 ns | 0.154 in, 3.9 mm Width | 16-SOIC | |
Texas Instruments CD74HCT123M96G4 | 2 | 5.5 V | 4.5 V | Surface Mount | Monostable | 16-SOIC | -55 °C | 125 °C | 4 mA, 4 mA | 25 ns | 0.154 in, 3.9 mm Width | 16-SOIC |
Key Features
• Overriding Reset Terminates Output PulseTriggering From the Leading or Trailing EdgeQ and Q\ Buffered OutputsSeparate ResetsWide Range of Output-Pulse WidthsSchmitt Trigger on Both A\ and B InputsFanout (Over Temperature Range)Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL LoadsBus Driver Outputs . . . . . . . . . . . . . 15 LSTTL LoadsWide Operating Temperature Range . . . –55°C to 125°CBalanced Propagation Delay and Transition TimesSignificant Power Reduction Compared to LSTTL Logic ICsHC Types2V to 6V OperationHigh Noise Immunity: NIL= 30%, NIH= 30% of VCCat VCC= 5VHCT Types4.5V to 5.5V OperationDirect LSTTL Input Logic Compatibility, VIL= 0.8V (Max), VIH= 2V (Min)CMOS Input Compatibility, Il1µA at VOL, VOHOverriding Reset Terminates Output PulseTriggering From the Leading or Trailing EdgeQ and Q\ Buffered OutputsSeparate ResetsWide Range of Output-Pulse WidthsSchmitt Trigger on Both A\ and B InputsFanout (Over Temperature Range)Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL LoadsBus Driver Outputs . . . . . . . . . . . . . 15 LSTTL LoadsWide Operating Temperature Range . . . –55°C to 125°CBalanced Propagation Delay and Transition TimesSignificant Power Reduction Compared to LSTTL Logic ICsHC Types2V to 6V OperationHigh Noise Immunity: NIL= 30%, NIH= 30% of VCCat VCC= 5VHCT Types4.5V to 5.5V OperationDirect LSTTL Input Logic Compatibility, VIL= 0.8V (Max), VIH= 2V (Min)CMOS Input Compatibility, Il1µA at VOL, VOH
Description
AI
The ’HC123, ’HCT123, 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 CXprovides 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.
Once triggered, the output pulse width may be extended by retriggering inputs A\ and B. The output pulse can be terminated by a LOW level on the Reset (R) pin. Trailing edge triggering (A)\ and leading edge triggering (B) inputs are provided for triggering from either edge of the input pulse. If either Mono is not used each input on the unused device (A\, B, and R\) must be terminated high or low.
The minimum value of external resistance, Rx is typically 5k. The minimum value external capacitance, CX, is 0pF. The calculation for the pulse width is tW= 0.45 RXCXat VCC= 5V.
The ’HC123, ’HCT123, 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 CXprovides 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.
Once triggered, the output pulse width may be extended by retriggering inputs A\ and B. The output pulse can be terminated by a LOW level on the Reset (R) pin. Trailing edge triggering (A)\ and leading edge triggering (B) inputs are provided for triggering from either edge of the input pulse. If either Mono is not used each input on the unused device (A\, B, and R\) must be terminated high or low.
The minimum value of external resistance, Rx is typically 5k. The minimum value external capacitance, CX, is 0pF. The calculation for the pulse width is tW= 0.45 RXCXat VCC= 5V.