MM74HC221AN Equivalent & Substitute Parts

Part Overview

The MM74HC221AN is a monostable multivibrator IC manufactured by onsemi, featuring dual independent circuits with Schmitt trigger inputs and 22 ns propagation delay. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. The 16-DIP through-hole package and 2V to 6V supply voltage range define its primary application scope in logic circuit design.

Substiute Parts

MM74HC221AN

onsemiIn Stock: 1101MM74HC221AN Datasheet

Current PartRFQ

CD74HC221E

Texas InstrumentsIn Stock: 19796CD74HC221E Datasheet

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SN74LV07AD

Texas InstrumentsIn Stock: 3469SN74LV07AD Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the MM74HC221AN is determined by the following critical parameters:

• Logic Function: Monostable multivibrator with dual independent circuits
• Schmitt Trigger Input: Required for noise immunity in timing applications
• Package Type: 16-DIP through-hole configuration for PCB compatibility
• Supply Voltage Range: 2V to 6V operation
• Output Current Capability: 5.2 mA minimum for both high and low states
• Propagation Delay: Maximum 22 ns for timing-critical applications

The CD74HC221E from Texas Instruments meets all functional and electrical requirements as a direct substitute. The SN74LV07AD, while sharing the 74-series logic family heritage, represents a different functional class (buffer vs. multivibrator) and is listed for reference only; it does not provide equivalent monostable multivibrator functionality.

Parameter Comparison

Engineering Selection Recommendations

CD74HC221E is the primary equivalent substitute for MM74HC221AN. Both devices share identical functional specifications, package geometry, and electrical characteristics. The CD74HC221E offers superior product status (Active vs. Obsolete) and extended operating temperature range (-55°C to 125°C vs. -40°C to 85°C). RoHS3 compliance of the CD74HC221E aligns with current manufacturing standards. Propagation delay of 18 ns on the CD74HC221E is faster than the 22 ns specification, providing improved timing performance without functional impact.

SN74LV07AD is not recommended as a functional substitute. Despite sharing the 74-series logic family designation, this device is a buffer with open-drain output, not a monostable multivibrator. The surface-mount 14-SOIC package is incompatible with through-hole PCB designs. Product status (Discontinued at DiGi Electronics) further limits its viability for new designs.

Frequently Asked Questions (FAQ)

Q: Can CD74HC221E directly replace MM74HC221AN in existing designs?

A: Yes. Both devices are 16-DIP through-hole packages with identical pinouts, supply voltage ranges (2V to 6V), and output current specifications (5.2 mA). The CD74HC221E's faster propagation delay (18 ns vs. 22 ns) is compatible with timing requirements specified for the MM74HC221AN.

Q: What is the significance of the propagation delay difference between MM74HC221AN (22 ns) and CD74HC221E (18 ns)?

A: Propagation delay defines the time interval between input signal transition and output response. The CD74HC221E's 18 ns delay is faster, meaning output transitions occur sooner. This improvement does not create compatibility issues; circuits designed for 22 ns operation function correctly with 18 ns devices.

Q: Why is SN74LV07AD listed if it cannot substitute for MM74HC221AN?

A: SN74LV07AD is included for reference to clarify functional differences within the 74-series logic family. This device performs buffer operations, not monostable multivibrator timing functions. Selection of SN74LV07AD would require complete circuit redesign and is not a valid substitute.

Q: Are there package compatibility considerations for through-hole vs. surface-mount alternatives?

A: Yes. MM74HC221AN and CD74HC221E are both 16-DIP through-hole packages suitable for traditional PCB assembly. SN74LV07AD uses 14-SOIC surface-mount packaging, requiring different PCB layout and assembly processes. Through-hole and surface-mount packages are not interchangeable without PCB redesign.

Q: What compliance certifications should be verified for new procurement?

A: CD74HC221E carries RoHS3 compliance certification, meeting current environmental and manufacturing standards. Verify REACH compliance status and ECCN classification (both listed as EAR99) with your procurement department for export and regulatory requirements specific to your application region.