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INTEGRATED CIRCUITS
DATA SHEET
For a complete data sheet, please also download:
• The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications
• The IC06 74HC/HCT/HCU/HCMOS Logic Package Information
• The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines
74HC/HCT123
Dual retriggerable monostable
multivibrator with reset
Product specification
Supersedes data of September 1993
File under Integrated Circuits, IC06
1998 Jul 08
Philips Semiconductors
Dual retriggerable monostable
multivibrator with reset
Product specification
74HC/HCT123
Fig.6 Timing component connections.
DC CHARACTERISTICS FOR 74HC
For the DC characteristics see “74HC/HCT/HCU/HCMOS Logic Family Specifications”.
Output capability: standard (except for nREXT/CEXT)
ICC category: MSI
1998 Jul 08
5
Philips Semiconductors
Dual retriggerable monostable
multivibrator with reset
APPLICATION INFORMATION
Power-up considerations
When the monostable is powered-up it may produce an
output pulse, with a pulse width defined by the values of RX
and CX, this output pulse can be eliminated using the
circuit shown in Fig.11.
Product specification
74HC/HCT123
Fig.11 Power-up output pulse elimination circuit.
Power-down considerations
A large capacitor (CX) may cause problems when
powering-down the monostable due to the energy stored
in this capacitor. When a system containing this device is
powered-down or a rapid decrease of VCC to zero occurs,
the monostable may substain damage, due to the
capacitor discharging through the input protection diodes.
To avoid this possibility, use a damping diode (DX)
preferably a germanium or Schottky type diode able to
withstand large current surges and connect as shown in
Fig.12
Fig.12 Power-down protection circuit.
1998 Jul 08
11