74HCT85N,652 Magnitude Comparator - Equivalent & Substitute Parts

Part Overview

The 74HCT85N,652 is a 4-bit magnitude comparator logic IC manufactured by NXP USA Inc., housed in a 16-DIP package. This component performs binary comparison operations with active high outputs for A<B, A=B, and A>B functions. The part is classified as obsolete, making identification of suitable substitutes essential for ongoing system support and component procurement.

Substiute Parts

74HCT85N,652

NXP USA Inc.In Stock: 96174HCT85N,652 Datasheet

Current PartRFQ

CD74HCT85E

Harris CorporationIn Stock: 1758CD74HCT85E Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 74HCT85N,652 is determined by strict equivalence across the following critical parameters:

• Functional equivalence: 4-bit magnitude comparator with identical output functions (A<B, A=B, A>B)
• Electrical compatibility: Supply voltage range 4.5V ~ 5.5V, output current capability 4mA, quiescent current 8 µA
• Timing performance: Maximum propagation delay specifications
• Package compatibility: 16-DIP through-hole mounting
• Series alignment: 74HCT logic family

The CD74HCT85E manufactured by Harris Corporation meets all functional and electrical requirements for direct substitution. Both parts share the same base product number (74HCT85) and deliver identical comparison logic with compatible electrical characteristics.

Parameter Comparison

Engineering Selection Recommendations

The CD74HCT85E serves as a direct functional equivalent to the 74HCT85N,652. Key considerations for component selection:

Compliance Status: The original 74HCT85N,652 is ROHS3 compliant, while the CD74HCT85E is RoHS non-compliant. Systems requiring RoHS compliance must account for this regulatory difference.

Temperature Range: The CD74HCT85E extends the lower operating temperature limit to -55°C compared to -40°C for the original part, providing broader environmental coverage.

Propagation Delay: The CD74HCT85E demonstrates superior timing performance at 40ns versus 44ns, representing a 9% improvement in switching speed at identical test conditions.

Packaging and Mounting: Both parts utilize identical 16-DIP through-hole packages, ensuring direct PCB compatibility without layout modifications.

Product Status: Both components are classified as obsolete. Long-term availability should be evaluated through component distributors.

Frequently Asked Questions (FAQ)

Q: Can the CD74HCT85E replace the 74HCT85N,652 in existing designs?

A: Yes. Both parts are 4-bit magnitude comparators with identical output functions, supply voltage requirements, output current ratings, and quiescent current specifications. The 16-DIP package pinout is identical, enabling direct substitution without circuit modification.

Q: What is the difference in propagation delay between these parts?

A: The CD74HCT85E has a maximum propagation delay of 40ns at 4.5V with 50pF load, compared to 44ns for the 74HCT85N,652. This 4ns difference represents faster switching performance and does not affect functional compatibility.

Q: Are there temperature range differences I should consider?

A: The CD74HCT85E operates from -55°C to 125°C, while the 74HCT85N,652 operates from -40°C to 125°C. If your application requires operation below -40°C, the CD74HCT85E provides extended low-temperature capability.

Q: What is the impact of RoHS compliance differences?

A: The 74HCT85N,652 is ROHS3 compliant; the CD74HCT85E is RoHS non-compliant. If your system or end-market requires RoHS certification, this difference must be addressed through design review or alternative component sourcing.

Q: Are the packages physically identical?

A: Yes. Both parts use 16-DIP (0.300", 7.62mm) through-hole packages with identical pinouts and mechanical dimensions, allowing direct PCB substitution.

Q: What is the base product number for these comparators?

A: Both the 74HCT85N,652 and CD74HCT85E share the base product number 74HCT85, confirming their functional equivalence within the 74HCT logic family.