74HCT123N,652 Equivalent & Substitute Parts

Part Overview

The 74HCT123N,652 is a monostable multivibrator logic integrated circuit manufactured by NXP USA Inc. in a 16-DIP package. This device features two independent circuits with a propagation delay of 77 ns and operates across a supply voltage range of 4.5 V to 5.5 V. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system maintenance and new design implementations where this specific part number is no longer available from primary sources.

Substiute Parts

74HCT123N,652

NXP USA Inc.In Stock: 93274HCT123N,652 Datasheet

Current PartRFQ

CD74HCT123E

Texas InstrumentsIn Stock: 2107CD74HCT123E Datasheet

MFR RecommendedRFQ

CD74HCT423E

Harris CorporationIn Stock: 8152CD74HCT423E Datasheet

MFR RecommendedRFQ

SN74LS221N

Texas InstrumentsIn Stock: 2179SN74LS221N Datasheet

MFR RecommendedRFQ

SN74LS423N

Texas InstrumentsIn Stock: 3442SN74LS423N Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74HCT123N,652 is determined by the following critical parameters: logic type (monostable multivibrator), number of independent circuits (2), package type (16-DIP through-hole), and supply voltage compatibility (4.5 V ~ 5.5 V). All substitute parts listed maintain these core functional and physical characteristics, ensuring pin-compatible replacement in existing circuit designs.

The substitute parts are grouped into two categories based on series designation and performance characteristics:

74HCT Series Substitutes: CD74HCT123E and CD74HCT423E maintain identical supply voltage ranges and improved propagation delay performance (25 ns versus 77 ns), with enhanced operating temperature ranges in certain variants.

74LS Series Substitutes: SN74LS221N and SN74LS423N provide functional equivalence with different electrical characteristics, including modified supply voltage ranges (4.75 V ~ 5.25 V) and output current specifications, suitable for applications where 74LS logic levels are acceptable.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (74HCT Series): CD74HCT123E is the preferred substitute, offering active product status, ROHS3 compliance, and improved propagation delay performance while maintaining identical supply voltage specifications. This part provides direct functional replacement with enhanced electrical characteristics.

Secondary Substitutes (74LS Series): SN74LS221N and SN74LS423N are suitable where 74LS logic family compatibility is acceptable. Both parts maintain active product status and ROHS3 compliance. Selection between these two depends on propagation delay requirements: SN74LS423N offers 28 ns delay versus SN74LS221N at 45 ns.

Compliance Considerations: CD74HCT423E, while functionally equivalent, carries RoHS non-compliance status and obsolete product designation, making it unsuitable for new designs requiring regulatory compliance. The 74LS series substitutes operate within a narrower supply voltage range (4.75 V ~ 5.25 V) and reduced temperature range (0°C ~ 70°C) compared to the original part, requiring verification against system specifications.

Frequently Asked Questions (FAQ)

Q: Can CD74HCT123E directly replace 74HCT123N,652 in existing designs?

A: Yes. Both parts share identical package type (16-DIP), pin configuration, supply voltage range (4.5 V ~ 5.5 V), and output current specifications (4 mA, 4 mA). CD74HCT123E provides improved propagation delay (25 ns versus 77 ns) and maintains ROHS3 compliance with active product status.

Q: What are the key differences between 74HCT and 74LS series substitutes?

A: The 74HCT series (CD74HCT123E, CD74HCT423E) maintains the original supply voltage range of 4.5 V ~ 5.5 V and output current of 4 mA per channel. The 74LS series (SN74LS221N, SN74LS423N) operates at 4.75 V ~ 5.25 V with reduced output current (400 µA high, 8 mA low) and narrower operating temperature range (0°C ~ 70°C). Selection depends on system power supply specifications and temperature requirements.

Q: Are all substitute parts pin-compatible with the original 74HCT123N,652?

A: Yes. All listed substitutes use the 16-DIP package with identical pin assignments for monostable multivibrator function. Physical and electrical pin compatibility is maintained across all substitute options.

Q: Which substitute offers the best performance improvement?

A: CD74HCT123E and CD74HCT423E both provide 25 ns propagation delay compared to the original 77 ns, representing a 68% improvement. Both maintain supply voltage compatibility and are available in active product status.

Q: What compliance certifications should I verify for new designs?

A: Verify ROHS3 compliance status and product availability. CD74HCT123E, SN74LS221N, and SN74LS423N all carry ROHS3 compliance. CD74HCT423E is RoHS non-compliant and should not be used in designs requiring regulatory compliance.