74HC27N NOR Gate IC Equivalent & Substitute Parts

Part Overview

The 74HC27N is a triple 3-input NOR gate logic integrated circuit manufactured by NXP USA Inc. in a 14-DIP through-hole package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The 74HC27 series represents a standard logic gate family widely used in digital circuit applications requiring NOR gate functionality with CMOS technology characteristics.

Substiute Parts

74HC27N,652

NXP USA Inc.In Stock: 96874HC27N,652 Datasheet

Current PartRFQ

CD74HC27E

Harris CorporationIn Stock: 1282CD74HC27E Datasheet

MFR RecommendedRFQ

SN74HC27N

Texas InstrumentsIn Stock: 14354SN74HC27N Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74HC27N is determined by strict equivalence across the following critical parameters:

• Logic function: Triple 3-input NOR gate
• Package format: 14-DIP through-hole configuration
• Electrical specifications: Supply voltage range, input/output current ratings, and logic level thresholds
• Pin configuration: Identical pinout within the 74HC27 base product family

Substitute parts must maintain functional and electrical compatibility within these defined parameters. The 74HC27 series from different manufacturers (NXP, Texas Instruments, Harris Corporation) share the same base product number and core specifications, enabling direct substitution where package and electrical characteristics align.

Parameter Comparison

Engineering Selection Recommendations

SN74HC27N (Texas Instruments) is the primary active substitute for the obsolete 74HC27N. This part maintains full electrical equivalence with identical propagation delay (15ns @ 6V, 50pF) and RoHS3 compliance. The operating temperature range of -40°C to 85°C covers standard industrial applications. Active product status ensures ongoing availability and manufacturing support.

CD74HC27E (Harris Corporation) provides functional equivalence with extended operating temperature range (-55°C to 125°C), suitable for applications requiring wider temperature operation. However, this part is obsolete and carries RoHS non-compliance status. Selection of this substitute should be limited to legacy system maintenance where temperature range requirements exceed standard specifications and compliance restrictions do not apply.

Both substitutes maintain identical logic function, pin configuration, and core electrical characteristics within the specified parameter ranges, enabling direct replacement in 14-DIP through-hole applications.

Frequently Asked Questions (FAQ)

Q: Can SN74HC27N directly replace 74HC27N in existing designs? A: Yes. Both parts share identical logic function, pin configuration, electrical specifications, and 14-DIP package format. Direct substitution is functionally compatible.

Q: What is the difference in propagation delay between the substitutes? A: SN74HC27N and 74HC27N both specify 15ns maximum propagation delay at 6V with 50pF load. CD74HC27E specifies 16ns under identical conditions. This 1ns difference is within typical circuit timing margins for standard logic applications.

Q: Are there temperature range considerations for substitute selection? A: SN74HC27N operates from -40°C to 85°C, matching the original 74HC27N range. CD74HC27E extends to -55°C to 125°C for applications requiring wider temperature operation. Verify application temperature requirements before selection.

Q: What compliance differences exist between substitutes? A: SN74HC27N maintains ROHS3 compliance matching the original part. CD74HC27E is RoHS non-compliant. Applications subject to RoHS requirements must use SN74HC27N or the original 74HC27N.

Q: Are all substitutes available in the same packaging? A: Yes. All three parts use 14-DIP (0.300", 7.62mm) through-hole packages with identical pinouts, enabling direct board-level substitution without layout modifications.

Q: Which substitute should be selected for new designs? A: SN74HC27N is the recommended choice for new designs due to active product status, full RoHS3 compliance, and guaranteed long-term availability from Texas Instruments.