74HCT221D SMD IC SO16

Looking for So16 Ic? 74HCT221D SMD IC SO16 is available at Zbotic with fast shipping across India.

74HCT221D SMD IC SO16

The 74HC/HCT221 stands as a high-speed CMOS logic device, offering a dual monostable multivibrator with reset functionality. Compatible with low power Schottky TTL (LSTTL) standards and conforming to JEDEC standard no. 7A, these devices ensure seamless integration into existing systems.

Each 74HC/HCT221 multivibrator module is equipped with an active LOW-going edge input (nA) and an active HIGH-going edge input (nB), both of which serve as enable inputs. Pulse triggering occurs at specific voltage thresholds, independent of input pulse transition times. The inclusion of Schmitt-trigger input circuitry for the nB inputs guarantees jitter-free triggering, even with inputs featuring slow transition rates, thereby enhancing noise immunity.

Once triggered, the outputs (nQ, nQ) operate independently of further transitions of nA and nB inputs, relying solely on the timing components. The duration of output pulses can be controlled and terminated using the overriding active LOW reset inputs (nRD). Input pulses of varying durations relative to the output pulse are supported.

Pulse width stability is maintained through internal compensation mechanisms, ensuring consistency across different VCC levels and temperature ranges. The relationship governing output pulse width is defined by a formula involving external timing components.

Pin assignments for the “221” mirror those of the “123,” facilitating easy substitution in systems not utilizing retrigger functionality. This can be achieved simply by adjusting the values of REXT and/or CEXT components as needed.

In essence, the 74HC/HCT221 offers reliability, versatility, and ease of integration, making it a preferred choice for applications demanding precision timing and robust performance.

Features

• Pulse width variance is typically less than ± 5%
• Pin-out identical to “123”
• Overriding reset terminates output pulse
• nB inputs have hysteresis for improved noise immunity
• Output capability: standard (except for nREXT/CEXT)
• ICC category: MSI

Package Includes

• 1 x 74HCT221D SMD IC SO16

Datasheet:

74HCT221D SMD IC SO16 Overview

The 74HCT221D is a dual monostable multivibrator in a compact SO16 surface-mount package designed for precise one-shot pulse generation. It features independent retriggerable channels with reset functionality, ideal for timing, delay, and pulse-shaping tasks in digital circuits.

Key Features of 74HCT221D SMD IC SO16

• Dual monostable multivibrator modules for two independent one-shot pulses
• Pulse width variance typically less than ±5% for high timing accuracy
• Active LOW-going edge trigger on nA and active HIGH-going edge Schmitt-triggered input on nB for noise immunity
• Overriding reset pin immediately terminates any output pulse
• Standard output drive compatible with low-power Schottky TTL; low ICC (MSI category)
• Compact SO16 SMD footprint, genuine parts with fast shipping from Zbotic

Applications and Use Cases

• Debouncing mechanical switches in embedded control panels
• Generating precise time delays or timeout pulses in microcontroller circuits
• Pulse stretching for serial data synchronization or communication interfaces
• Retriggerable delay elements in sensor signal conditioning
• Reset-pulse generation for digital systems and watchdog timers

How to Use 74HCT221D SMD IC SO16

Solder the 74HCT221D into a matching SO16 footprint on your PCB, connect VCC and GND per standard HCT guidelines, then wire your trigger sources to the nA (active LOW) and nB (Schmitt-triggered, active HIGH) pins. Attach an external resistor and capacitor to the timing pins to set the one-shot pulse duration, and use the reset pin to abort pulses as needed. Apply edge triggers to generate precise output pulses on Q and Q̅.

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Frequently Asked Questions

What package does the 74HCT221D come in?

The 74HCT221D is supplied in a compact SO16 surface-mount package, making it ideal for high-density PCB layouts.

How accurate are the pulse outputs?

This IC delivers pulse widths with variance typically less than ±5%, ensuring consistent and precise timing for your circuits.

How do I stop an ongoing pulse?

Driving the reset pin to its active level immediately terminates any active output pulse, allowing you to abort or retrigger pulses as required.