MM74HC4538N Equivalent & Substitute Parts

Part Overview

The MM74HC4538N is a monostable multivibrator logic IC manufactured by onsemi, featuring dual independent circuits with Schmitt trigger inputs. This 16-pin DIP package device operates across a 2V to 6V supply range with a propagation delay of 26 ns and is rated for -40°C to 85°C operation. The product is classified as obsolete, making identification of functionally equivalent alternatives essential for design continuity and component sourcing in legacy system maintenance and reproduction applications.

Substiute Parts

MM74HC4538N

onsemiIn Stock: 1355MM74HC4538N Datasheet

Current PartRFQ

CD74HC4538E

Harris CorporationIn Stock: 2188CD74HC4538E Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MM74HC4538N is determined by strict alignment across the following critical parameters:

• Logic Function: Monostable multivibrator with dual independent circuits
• Schmitt Trigger Input: Required feature
• Package Type: 16-DIP (0.300", 7.62mm) through-hole mounting
• Supply Voltage Range: 2 V ~ 6 V compatibility
• Output Current Capability: 5.2 mA minimum for both high and low states
• Base Product Series: 74HC4538 logic family

The CD74HC4538E, manufactured by Harris Corporation, meets all substitution criteria. Both devices share the identical 74HC4538 base product number, confirming functional and pin-level equivalence. Differences in propagation delay (21 ns vs. 26 ns) and operating temperature range (-55°C ~ 125°C vs. -40°C ~ 85°C) represent performance enhancements rather than compatibility limitations, as the substitute operates within the original device's specified parameters while offering improved speed and thermal range.

Parameter Comparison

Engineering Selection Recommendations

Both the MM74HC4538N and CD74HC4538E are classified as obsolete products. Selection between these devices should be based on the following factors:

MM74HC4538N (onsemi): Suitable for applications where the original design specification requires the onsemi manufacturer variant or where the -40°C ~ 85°C operating range is sufficient. Current inventory availability is 1,340 pieces.

CD74HC4538E (Harris Corporation): Appropriate for applications requiring extended operating temperature range (-55°C ~ 125°C) or improved propagation delay performance (21 ns). This device offers superior thermal specifications and faster switching characteristics while maintaining full functional compatibility. Current inventory availability is 2,140 pieces.

Both devices carry identical ECCN (EAR99) and HTSUS (8542.39.0001) classifications. The CD74HC4538E is RoHS non-compliant, consistent with its obsolete status. Selection should prioritize application requirements for temperature range and timing performance, with inventory availability as a secondary consideration.

Frequently Asked Questions (FAQ)

Q: Are MM74HC4538N and CD74HC4538E pin-compatible?

A: Yes. Both devices share the 74HC4538 base product number and are housed in identical 16-DIP (0.300", 7.62mm) packages with through-hole mounting. Pin configuration and functional behavior are equivalent.

Q: What is the significance of the propagation delay difference (26 ns vs. 21 ns)?

A: The CD74HC4538E exhibits faster switching response. In timing-critical applications, this 5 ns improvement may be beneficial. However, both devices operate within standard 74HC logic family specifications and are compatible with designs originally specified for the MM74HC4538N.

Q: Can the CD74HC4538E replace the MM74HC4538N in all applications?

A: The CD74HC4538E is functionally equivalent and offers enhanced specifications (wider temperature range, faster propagation delay). It is suitable as a direct replacement in all applications where the MM74HC4538N was originally specified, provided that RoHS compliance is not a design requirement.

Q: Why are both devices classified as obsolete?

A: Both the MM74HC4538N and CD74HC4538E are legacy 74HC logic components. Modern designs typically employ programmable logic devices or newer logic families. These devices remain available through inventory channels for legacy system maintenance and reproduction applications.

Q: What are the supply voltage compatibility requirements?

A: Both devices operate across the identical 2 V ~ 6 V supply range. They are compatible with standard TTL and CMOS logic voltage levels within this specification.

Q: Are there any compliance or certification differences between these devices?

A: Both devices carry the same ECCN (EAR99) and HTSUS (8542.39.0001) classifications. The CD74HC4538E is RoHS non-compliant, which is typical for obsolete logic components. Compliance requirements should be evaluated based on application and regulatory jurisdiction.