MM74HC251N Equivalent & Substitute Parts

Part Overview

The MM74HC251N is a 1 x 8:1 multiplexer logic integrated circuit manufactured by onsemi in a 16-DIP package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The MM74HC251N operates from a single supply voltage of 2V to 6V and is designed for through-hole mounting applications requiring multiplexing functionality across eight input channels.

Substiute Parts

MM74HC251N

onsemiIn Stock: 4294MM74HC251N Datasheet

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CD74HC251E

Harris CorporationIn Stock: 31561CD74HC251E Datasheet

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SN74HC251N

Texas InstrumentsIn Stock: 2222SN74HC251N Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the MM74HC251N is determined by the following critical parameters:

• Circuit configuration (1 x 8:1 multiplexer topology)
• Package type (16-DIP through-hole)
• Voltage supply compatibility (2V ~ 6V single supply)
• Output current capability
• Operating temperature range compatibility
• Base product number (74HC251 series)

The identified substitute parts maintain the same functional circuit configuration and package footprint, ensuring direct replacement capability in existing PCB designs. Substitutes are grouped based on manufacturer origin and product status classification.

Parameter Comparison

Engineering Selection Recommendations

SN74HC251N (Texas Instruments) is the primary substitute option. This part maintains identical voltage supply and operating temperature specifications to the MM74HC251N while offering active product status, ensuring continued availability and manufacturing support. The SN74HC251N provides higher output current capability (7.8mA versus 5.2mA), which represents an improvement in drive capability without introducing compatibility issues. RoHS3 compliance certification provides environmental and regulatory alignment for modern manufacturing standards.

CD74HC251E (Harris Corporation) serves as an alternative substitute. This part maintains identical electrical specifications for voltage supply and output current to the MM74HC251N. The extended operating temperature range (-55°C ~ 125°C) provides broader environmental coverage. However, this part carries obsolete product status classification, limiting long-term procurement viability.

For new designs or long-term production requirements, SN74HC251N is the recommended selection. For legacy system maintenance where immediate substitution is required, CD74HC251E provides functional equivalence with identical electrical performance.

Frequently Asked Questions (FAQ)

Q: Can SN74HC251N directly replace MM74HC251N in existing designs?

A: Yes. Both parts share identical package geometry (16-DIP), voltage supply range (2V ~ 6V), and circuit configuration (1 x 8:1 multiplexer). The higher output current specification of SN74HC251N (7.8mA) is compatible with designs rated for the MM74HC251N (5.2mA) output current.

Q: What is the difference between CD74HC251E and SN74HC251N?

A: Both parts provide equivalent 1 x 8:1 multiplexer functionality in 16-DIP packages. CD74HC251E offers extended operating temperature range (-55°C ~ 125°C) compared to SN74HC251N (-40°C ~ 85°C). SN74HC251N maintains active product status, while CD74HC251E is classified as obsolete. Output current specifications are identical (5.2mA for CD74HC251E, 7.8mA for SN74HC251N).

Q: Are there package alternatives to 16-DIP for the 74HC251 multiplexer?

A: The provided data specifies only 16-DIP package availability for these parts. Alternative package options are not included in this reference.

Q: Does operating temperature range affect substitution compatibility?

A: Operating temperature range does not prevent substitution if the application operates within the overlapping temperature window. Both MM74HC251N and SN74HC251N operate across -40°C ~ 85°C. CD74HC251E extends to -55°C ~ 125°C, providing broader coverage for extreme temperature applications.

Q: What is the significance of product status (Active vs. Obsolete)?

A: Active product status indicates ongoing manufacturing and supplier support. Obsolete status indicates discontinued production. For long-term procurement and new designs, active parts ensure availability. Obsolete parts may have limited stock and no future manufacturing commitments.