74HC221N

芯片, 74HC CMOS逻辑器件

The is a dual non-retriggerable Monostable Multivibrator with a reset. It is pin compatible with the low power Schottky TTL LSTTL. Each multivibrator features an active low-going edge input nA\\ and an active high-going edge input nB, either of which can be used as an enable input. Pulse triggering occurs at a particular voltage level and is not directly related to the transition time of the input pulse. Schmitt-trigger input circuitry for the nB inputs allow jitter-free triggering from inputs with slow transition rates, providing the circuit with excellent noise immunity. Once triggered, the outputs nQ, nQ\\ are independent of further transitions of nA\ and nB inputs and are a function of the timing components. The output pulses can be terminated by the overriding active low reset inputs nRD\\. Input pulses may be of any duration relative to the output pulse.

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Pulse width variance is typically less than ±5%

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Pin-out identical to "123"

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Overriding reset terminates output pulse

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nB Inputs have hysteresis for improved noise immunity

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Output capability - Standard except for nREXT/CEXT

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Complies with JEDEC standard No. 7A