1. General description

The 74HC123; 74HCT123 is a dual retriggerable monostable multivibrator with reset. The basic

output pulse width is programmed by selection of external components (REXT and CEXT). Once

triggered this basic pulse width may be extended by retriggering either of the edge triggered

inputs (nA or nB). By repeating this process, the output pulse period (nQ = HIGH, nQ = LOW)

can be made as long as desired. Alternatively, an output delay can be terminated at any time by

a LOW-going edge on input nRD. Inputs include clamp diodes. This enables the use of current

limiting resistors to interface inputs to voltages in excess of VCC.

Schmitt-trigger action in the nA and nB inputs, makes the circuit highly tolerant to slower input rise

and fall times.

2. Features and benefits

• Wide supply voltage range from 2.0 V to 6.0 V

• CMOS low power dissipation

• High noise immunity

• Latch-up performance exceeds 100 mA per JESD 78 Class II Level B

• Complies with JEDEC standards:

• JESD8C (2.7 V to 3.6 V)

• JESD7A (2.0 V to 6.0 V)

• Input levels:

• For 74HC123: CMOS level

• For 74HCT123: TTL level

• DC triggered from active HIGH or active LOW inputs

• Retriggerable for very long pulses up to 100 duty factor

• Direct reset terminates output pulse

• Schmitt-trigger action on all inputs except for the reset input

• ESD protection:

• HBM JESD22-A114F exceeds 2000 V

• MM JESD22-A115-A exceeds 200 V

• Multiple package options

• Specified from -40 °C to +85 °C and from -40 °C to +125 °C

74HC123PW属于集成电路（IC） > 多谐振荡器。安世半导体(中国)有限公司制造生产的74HC123PW多谐振荡器多谐振荡器是简单的双态器件，尽管它们的典型使用方式在很大程度上具有模拟特性，但通常被认为是数字逻辑元器件。单稳型也称为“单发”，具有一种稳定状态；但施加触发信号可使它们离开此状态一段时间，该时间通常由所连接电容器的值来确定。这些器件对于去弹跳开关触头等应用非常有用。非稳型没有稳定状态，在两个状态之间按一定频率持续转换，该频率通常也是由所连接电容器的值来确定。