1. General description

The 74HCT4538 is a dual retriggerable-resettable monostable multivibrator. Each multivibrator has

two trigger/retrigger inputs (nA and nB), a direct reset input (nCD), two complementary outputs (nQ

and nQ), and two pins (nREXT/CEXT and nCEXT) for connecting the external timing components

CEXT and REXT. Typical pulse width variation over temperature range is ± 0.2 . The device

may be triggered by either the positive or the negative edges of the input pulse. The duration

and accuracy of the output pulse are determined by the external timing components CEXT and

REXT. The output pulse width (TW) is equal to 0.7 × REXT × CEXT. The linear design techniques

guarantee precise control of the output pulse width. A LOW level at nCD terminates the output

pulse immediately. Schmitt-trigger action in the trigger inputs makes the circuit highly tolerant to

slower rise and fall times. Inputs include clamp diodes. This enables the use of current limiting

resistors to interface inputs to voltages in excess of VCC.

2. Features and benefits

• Tolerant of slow trigger rise and fall times

• High noise immunity

• Separate reset inputs

• Triggering from falling or rising edge

• Complies with JEDEC standard no. 7A

• Wide supply voltage range from 4.5 to 5.5 V

• CMOS low power dissipation

• TTL input levels

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

• ESD protection:

• HBM JESD22-A114F exceeds 2000 V

• MM JESD22-A115-A exceeds 200 V

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

74HCT4538PW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74HCT4538PW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。