MM74HCT540N Equivalent & Substitute Parts

Part Overview

The MM74HCT540N is an inverting buffer logic integrated circuit manufactured by onsemi, designed for 5.5V operation with 3-state output capability. This 20-pin DIP package device functions as a single-element, 8-bit buffer with inverting logic configuration. The product is currently classified as obsolete, making equivalent substitute parts necessary for ongoing design support, maintenance, and production continuity in applications requiring this specific logic function and package format.

Substiute Parts

MM74HCT540N

onsemiIn Stock: 1780MM74HCT540N Datasheet

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CD74HCT540E

Harris CorporationIn Stock: 1747CD74HCT540E Datasheet

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SN74HCT540N

Texas InstrumentsIn Stock: 2133SN74HCT540N Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the MM74HCT540N are qualified based on the following critical parameters that determine functional and mechanical compatibility:

• Logic Function: Buffer, Inverting configuration with identical 1 element, 8-bit per element architecture
• Output Configuration: 3-State output capability
• Supply Voltage: 4.5V ~ 5.5V operating range
• Package Format: 20-DIP (0.300", 7.62mm) through-hole mounting
• Base Product Series: 74HCT logic family

The substitute parts CD74HCT540E and SN74HCT540N meet all these core electrical and mechanical requirements, enabling direct functional replacement in circuit designs currently using the MM74HCT540N.

Parameter Comparison

Engineering Selection Recommendations

SN74HCT540N (Texas Instruments) is the preferred substitute for new designs and production applications. This part maintains active product status, ensuring long-term availability and supply chain stability. The SN74HCT540N is ROHS3 compliant, meeting current environmental and regulatory requirements. Operating temperature range (-40°C ~ 85°C) matches the original MM74HCT540N specification, and output current specifications (6mA) are within acceptable tolerance for standard 74HCT logic applications.

CD74HCT540E (Harris Corporation) provides functional equivalence with extended operating temperature range (-55°C ~ 125°C), suitable for applications requiring broader thermal performance. However, this part carries obsolete status and RoHS non-compliant designation, limiting its use to legacy system maintenance or specialized temperature-range requirements where regulatory compliance is not a constraint.

Both substitute parts share identical package geometry, pin configuration, and core logic function, enabling direct socket replacement without circuit board modification.

Frequently Asked Questions (FAQ)

Q: Can the CD74HCT540E and SN74HCT540N be used interchangeably with the MM74HCT540N?

A: Yes, both parts are functionally equivalent substitutes. All three devices share identical logic configuration (Buffer, Inverting), 8-bit architecture, 3-state output, 4.5V ~ 5.5V supply voltage, and 20-DIP package format. Direct socket replacement is possible without circuit redesign.

Q: What is the difference in output current between the MM74HCT540N and its substitutes?

A: The MM74HCT540N specifies 7.2mA output current (high and low), while both CD74HCT540E and SN74HCT540N specify 6mA. This difference is within standard 74HCT logic family tolerance and does not affect functional compatibility in typical applications.

Q: Which substitute part should be selected for new production?

A: The SN74HCT540N from Texas Instruments is recommended for new production due to active product status and ROHS3 compliance. This ensures regulatory alignment and long-term supply availability.

Q: Does the extended temperature range of the CD74HCT540E (-55°C ~ 125°C) provide an advantage?

A: The extended temperature range applies only if the application requires operation outside the standard -40°C ~ 85°C specification. For applications within standard operating conditions, temperature range difference is not a selection factor.

Q: Are there any package or pinout differences between these parts?

A: No. All three parts use identical 20-DIP (0.300", 7.62mm) through-hole package format with matching pin configuration, enabling direct board-level substitution.

Q: What compliance considerations apply to substitute selection?

A: The SN74HCT540N is ROHS3 compliant and suitable for applications with environmental or regulatory requirements. The CD74HCT540E is RoHS non-compliant and should be used only in legacy systems or applications where compliance is not mandated.