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NXP Semiconductors 74HC221N,652
- Part No.:
- 74HC221N,652
- Manufacturer:
- NXP Semiconductors
- Category:
- Multivibrators
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
74HC221N,652.pdf
- Description:
- IC MULTIVIBRATOR 19NS 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,166
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Product details
Overview
74HC221N,652 from Nexperia is a dual non-retriggerable monostable multivibrator with independent reset inputs, designed for precise pulse generation and timing control in digital logic systems. It features two identical monostable circuits, each with negative-edge (nA) and positive-edge (nB) trigger inputs, active-low reset (nRD), complementary outputs (nQ/nQ), and external REXT/CEXT timing networks. Typical output pulse width stability is ±5%, with propagation delays as low as 21 ns at VCC = 4.5 V - used in debounce circuits, event timing, and clock stretching in industrial control interfaces.
For engineers reviewing the 74HC221N,652 datasheet, 74HC221N,652 pinout, 74HC221N,652 application, or 74HC221N,652 equivalent, key selection considerations include non-retriggerable behavior, Schmitt-triggered nB inputs for noise immunity, dual independent timing channels, reset override capability, and compatibility with 2–6 V CMOS supply rails.
Technical Context
The 74HC221N,652 implements two independent monostable multivibrators using high-speed Si-gate CMOS technology, compliant with JEDEC standard no. 7A and pin-compatible with LSTTL. Each channel accepts either a falling edge on nA or rising edge on nB to initiate a single output pulse - retriggering is blocked until completion, ensuring deterministic timing.
Timing is set externally via resistor-capacitor networks connected to dedicated pins (e.g., 1REXT/CEXT, 2REXT/CEXT, 1CEXT, 2CEXT), with pulse width defined by tW ≈ 0.7 × REXT × CEXT. Internal compensation ensures pulse width stability across VCC (2–6 V) and temperature (−40 °C to +125 °C), limited only by component tolerance of external R and C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 2.0 V to 6.0 V - supports mixed-voltage system interfacing and battery-powered logic |
| Propagation Delay (nA→nQ) | 21 ns min / 35 ns typ at VCC = 4.5 V - enables sub-50 ns timing resolution in fast logic paths |
| Output Pulse Width Range | 140 ns to 805 µs - adjustable via external REXT (2–1000 kΩ) and CEXT (no limits) networks |
| Pulse Width Stability | ±5% typical - achieved via internal compensation, minimizing drift with VCC and temperature |
| Input Hysteresis (nB) | Present - provides jitter-free triggering from slow-rising or noisy signals in industrial environments |
| Reset Override | Active LOW (nRD) terminates ongoing output pulse immediately - critical for fault recovery and priority interrupt handling |
| Operating Temperature | −40 °C to +125 °C - qualified for automotive under-hood and industrial motor control applications |
Pinout & Package
DIP-16 package (plastic dual in-line, 0.3 inch body width), lead finish SnPb, RoHS-compliant variant available. Pin 8 = GND; Pin 16 = VCC; dual-channel symmetry evident in pin numbering (1/9 = 1A/2A, 3/11 = 1RD/2RD, etc.).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 9 | 1A, 2A - negative-edge trigger inputs | Falling-edge sensitive; initiates monostable pulse when asserted; no hysteresis |
| 2, 10 | 1B, 2B - positive-edge trigger inputs | Rising-edge sensitive with Schmitt-trigger hysteresis for noise immunity |
| 3, 11 | 1RD, 2RD - active-LOW reset inputs | Forces nQ LOW and nQ HIGH immediately, overriding ongoing output pulse |
| 4, 12 | 1Q, 2Q - active-LOW outputs | Complementary to nQ; sinks current during pulse; standard logic drive capability |
| 5, 13 | 1Q, 2Q - active-HIGH outputs | Complementary to nQ; sources current during pulse; standard logic drive capability |
| 6, 14 | 1CEXT, 2CEXT - external capacitor connections | Connect timing capacitors; recommended to ground externally per datasheet Note |
| 7, 15 | 2REXT/CEXT, 1REXT/CEXT - R/C common nodes | Shared connection point for timing resistor and capacitor; defines tW = 0.7 × REXT × CEXT |
| 8 | GND | Ground reference for all internal circuitry and I/O |
| 16 | VCC | Positive supply rail; powers internal logic and output stages |
Key Features
| Feature | Design Value |
|---|---|
| Non-retriggerable operation | Prevents pulse extension from repeated triggers - essential for fixed-duration timing in safety-critical sequencing |
| Dual independent monostables | Enables concurrent timing of two events (e.g., enable delay + timeout) without cross-talk or shared components |
| Overriding active-LOW reset | Guarantees immediate termination of output pulse regardless of trigger state - used in emergency stop logic |
| Pin-out identical to 74LS123 | Allows drop-in replacement in legacy TTL designs without PCB modification when supply and loading permit |
| Wide VCC range (2–6 V) | Supports direct interface with 3.3 V microcontrollers and 5 V legacy peripherals without level-shifting |
Applications
| Keyboard Debounce | Industrial Sensor Timing |
|---|---|
|
Use Scenario: Mechanical keypresses generate multiple contact bounces lasting 5–20 ms, causing false register reads in microcontroller GPIO. IC Role / Device Role / Timing Role: 74HC221N,652 acts as hardware debounce timer - one-shot triggered by first bounce edge, holding clean output stable for ≥20 ms. Use Value: Eliminates software polling or firmware debouncing overhead; guarantees single-edge detection per press with <1 µs jitter. |
Use Scenario: A proximity sensor detects metal presence but requires a fixed 100 ms window to confirm valid actuation and reject EMI-induced glitches. IC Role / Device Role / Timing Role: 74HC221N,652 generates precise 100 ms pulse upon sensor edge, enabling downstream logic to gate measurement windows. Use Value: Provides deterministic, temperature-stable timing independent of MCU clock accuracy or software latency. |
| Power Sequencing Control | Legacy Bus Arbitration |
|
Use Scenario: A multi-rail power supply must assert 3.3 V before enabling 1.8 V, with minimum 10 ms delay between rails to prevent latch-up. IC Role / Device Role / Timing Role: 74HC221N,652 provides fixed-delay assertion of second rail enable signal, triggered by first rail's power-good flag. Use Value: Ensures safe, repeatable power-up sequence without FPGA or processor involvement - improves system reliability. |
Use Scenario: An 8-bit microcontroller shares an address/data bus with a DMA controller; bus grant must be held for ≥500 ns after request to avoid contention. IC Role / Device Role / Timing Role: 74HC221N,652 extends bus grant signal duration to meet minimum hold time, triggered by GRANT# edge. Use Value: Guarantees compliance with bus timing specifications without modifying core controller firmware or adding glue logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar monostable multivibrator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC221APWR | 3.3 V only (1.65–3.6 V); lower propagation delay (13 ns typ); no internal hysteresis on B inputs | Optimized for modern low-voltage digital systems; lacks noise immunity for slow/noisy triggers | Select when operating exclusively at 3.3 V and input signals are clean; verify external hysteresis if needed |
| 74HCT221N,652 | TTL-input compatible (VIH = 2.0 V min); identical pinout and timing; higher ICC at VCC = 5 V | Direct replacement where legacy 5 V TTL logic drives inputs; maintains same pulse width accuracy | Choose for mixed TTL/CMOS systems or when driving from 5 V LSTTL outputs without level shifters |
Compared with SN74LVC221APWR and 74HCT221N,652, the 74HC221N,652 offers widest supply range (2–6 V), built-in nB hysteresis, and guaranteed operation to +125 °C - making it optimal for industrial and automotive timing where voltage flexibility and noise resilience are critical.
Availability
74HC221N,652 is available at Aetrix Electronics and suitable for industrial control panels, automotive body electronics, and legacy system upgrades requiring stable component supply, long-term obsolescence management, and full traceability.
Supply support for 74HC221N,652 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Nexperia is a global leader in discrete, logic, and PowerMOS semiconductors, spun off from NXP's Standard Products division in 2017 and focused on automotive, industrial, computing, and consumer markets.
The 74HC221N,652 belongs to Nexperia's 74HC high-speed CMOS logic family - engineered for pin compatibility with legacy TTL, wide supply range, and robust performance in harsh environments.
FAQ
What is the maximum operating temperature for the 74HC221N,652?
The 74HC221N,652 is rated for operation from −40 °C to +125 °C. This extended temperature range is validated per AC characteristics tables in the official Nexperia datasheet and supports use in under-hood automotive modules and industrial motor drives where ambient temperatures exceed 85 °C.
Can the 74HC221N,652 generate asymmetric pulse widths on its two channels?
Yes - the 74HC221N,652 supports independent timing networks: Channel 1 uses pins 15 (1REXT/CEXT) and 14 (1CEXT), while Channel 2 uses pins 7 (2REXT/CEXT) and 6 (2CEXT). By selecting different REXT and CEXT values per channel, distinct pulse widths (e.g., 10 ms and 100 ms) can be generated simultaneously without interaction.
Is the 74HC221N,652 pin-compatible with the 74LS123?
Yes - the 74HC221N,652 has identical pin assignments to the 74LS123, as confirmed in the "Pin configuration" section of the Nexperia datasheet. This allows direct substitution in existing designs, provided supply voltage (2–6 V vs. 4.75–5.25 V) and output loading are verified for compatibility.
Does the 74HC221N,652 require external pull-up resistors on its inputs?
No - the 74HC221N,652 does not require external pull-ups. Its nA and nRD inputs are standard CMOS with high-impedance logic thresholds; nB inputs include Schmitt-trigger hysteresis. Pull-ups are only needed if system-level signal integrity demands biasing for floating inputs - not a device requirement.
How is pulse width calculated for the 74HC221N,652?
The output pulse width tW of the 74HC221N,652 is calculated as tW = 0.7 × REXT × CEXT, where REXT is connected between VCC and the REXT/CEXT pin (e.g., pin 15), and CEXT is connected between that same pin and GND (pin 8). This relationship holds across VCC = 2–6 V and is confirmed in the General Description and Quick Reference Data sections of the datasheet.
74HC221N,652 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- 74HC
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Monostable
- Independent Circuits:
- 2
- Schmitt Trigger Input:
- Yes
- Propagation Delay:
- 19 ns
- Current - Output High, Low:
- 5.2mA, 5.2mA
- Voltage - Supply:
- 2 V ~ 6 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-DIP
74HC221N,652 FAQ
1.How can I place an order for 74HC221N,652 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74HC221N,652 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for 74HC221N,652 reliable?
The price and inventory of 74HC221N,652 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HC221N,652 is usually 5 days.
3.What payment methods are accepted for 74HC221N,652?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HC221N,652 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74HC221N,652?
74HC221N,652 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74HC221N,652 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for 74HC221N,652?
For technical support, including 74HC221N,652 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HC221N,652 requirements.
6.How does Aetrix verify that 74HC221N,652 is sourced from the original manufacturer or authorized distributors?
All 74HC221N,652 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 74HC221N,652 meets industry standards.
7.What is the process for return or replacement of 74HC221N,652?
All 74HC221N,652 units undergo pre-shipment inspection (PSI). If there is an issue with 74HC221N,652, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The 74HC221N,652 part is unused and in its original packaging.
Return procedure for 74HC221N,652:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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