74ACT257SCX Equivalent & Substitute Parts

Part Overview

The 74ACT257SCX is a 4 x 2:1 multiplexer logic IC manufactured by onsemi in a 16-SOIC surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The 74ACT257SCX operates from a single 4.5V to 5.5V supply with output drive capability of 24mA high and low, suitable for standard TTL logic applications requiring multiplexing functionality.

Substiute Parts

74ACT257SCX

onsemiIn Stock: 984274ACT257SCX Datasheet

Current PartRFQ

MC74ACT157DR2G

onsemiIn Stock: 5604MC74ACT157DR2G Datasheet

Parametric EquivalentRFQ

MC74ACT257DR2G

onsemiIn Stock: 2766MC74ACT257DR2G Datasheet

Parametric EquivalentRFQ

74AHCT257D,118

Nexperia USA Inc.In Stock: 339074AHCT257D,118 Datasheet

SimilarRFQ

CD74ACT257M

Harris CorporationIn Stock: 2314CD74ACT257M Datasheet

SimilarRFQ

CD74ACT257M96

Texas InstrumentsIn Stock: 5625CD74ACT257M96 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 74ACT257SCX is determined by the following critical parameters: circuit configuration (4 x 2:1 multiplexer), package type (16-SOIC), supply voltage range (4.5V ~ 5.5V), and mounting method (surface mount). Parts are grouped into two categories:

Parametric Equivalents maintain identical electrical specifications including output drive current (24mA) and operating temperature range (-40°C ~ 85°C). These parts are direct functional replacements with no design modifications required.

Similar Parts share the same circuit configuration and package but differ in output drive current or operating temperature range. These require design verification to confirm compatibility with the application's current and temperature requirements.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Parametric Equivalents): MC74ACT257DR2G and MC74ACT157DR2G are active production parts from onsemi with identical electrical specifications to the 74ACT257SCX. Both maintain 24mA output drive and -40°C to 85°C operating range. MC74ACT257DR2G is available in Tape & Reel packaging, suitable for automated assembly. These parts require no circuit modifications.

Secondary Substitutes (Similar Parts): CD74ACT257M96 from Texas Instruments is an active production part with higher output drive capability (75mA) and extended operating temperature range (-55°C to 125°C). This part is suitable for applications requiring greater current drive or wider temperature operation. The 74AHCT257D,118 from Nexperia is an active part with reduced output drive (8mA) and extended temperature range (-40°C to 125°C), appropriate for low-power applications.

Obsolete Parts: CD74ACT257M from Harris Corporation shares similar electrical characteristics but is obsolete. This part should be avoided for new designs unless existing inventory is available and application requirements are confirmed.

Frequently Asked Questions (FAQ)

Q: Can MC74ACT257DR2G directly replace 74ACT257SCX without circuit modifications? A: Yes. MC74ACT257DR2G maintains identical output drive current (24mA), supply voltage range (4.5V ~ 5.5V), and operating temperature range (-40°C ~ 85°C). The only difference is packaging format (Tape & Reel versus Tube) and active product status.

Q: What is the difference between MC74ACT257DR2G and MC74ACT157DR2G? A: Both parts are parametric equivalents with identical electrical specifications. The difference lies in the base product number designation (74ACT257 versus 74ACT157), though they function identically in this 4 x 2:1 multiplexer configuration.

Q: Can CD74ACT257M96 be used as a direct replacement? A: CD74ACT257M96 is functionally compatible but has higher output drive current (75mA versus 24mA) and extended operating temperature (-55°C to 125°C versus -40°C to 85°C). Verify that the application can tolerate increased current draw and confirm thermal design if operating at extended temperatures.

Q: Why is 74AHCT257D,118 listed as a similar part rather than an equivalent? A: The 74AHCT257D,118 has reduced output drive current (8mA versus 24mA). Applications requiring the full 24mA output drive cannot use this part without circuit redesign. Verify load requirements before selection.

Q: What packaging considerations apply to these substitutes? A: The 74ACT257SCX uses Tube packaging. Most active substitutes (MC74ACT257DR2G, MC74ACT157DR2G, 74AHCT257D,118, CD74ACT257M96) are available in Tape & Reel format, which is standard for automated assembly. Confirm packaging compatibility with your procurement and assembly processes.

Q: Are all substitute parts RoHS compliant? A: MC74ACT257DR2G, MC74ACT157DR2G, 74AHCT257D,118, and CD74ACT257M96 are ROHS3 compliant. CD74ACT257M is RoHS non-compliant. Verify RoHS compliance requirements for your application and region.