74ACT157SCX Equivalent & Substitute Parts

Part Overview

The 74ACT157SCX is a 4x2:1 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 new designs and ongoing production requirements. The 74ACT157 series provides single-supply operation with standard TTL-compatible logic levels, suitable for data selection and routing applications in digital systems.

Key Parameters

Parameter	Value
Part Number	74ACT157SCX
Manufacturer	onsemi
Circuit Type	4 x 2:1 Multiplexer
Output Current (High/Low)	24mA / 24mA
Supply Voltage Range	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package Type	16-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the 74ACT157SCX is determined by the following critical parameters:

Circuit Configuration: 4x2:1 multiplexer topology
Output Current Capability: 24mA source/sink (primary criterion)
Supply Voltage: 4.5V ~ 5.5V single supply
Package: 16-SOIC form factor
Mounting: Surface mount compatibility

Substitute parts are grouped into three categories:

Direct Manufacturer Substitutes maintain identical electrical specifications and packaging from the original manufacturer (onsemi), differing only in product status or packaging format (Tape & Reel vs. bulk).

Similar Manufacturer Substitutes provide equivalent circuit functionality and package form factor but may originate from alternative manufacturers (Nexperia, Harris, Texas Instruments) with minor parameter variations within acceptable ranges.

Parametric Equivalents share the same circuit topology and electrical performance but use different base part numbers (74ACT257 vs. 74ACT157), indicating functional equivalence with potential pinout or feature differences requiring design verification.

Parameter Comparison

Part Number	Manufacturer	Circuit	Output Current (mA)	Supply Voltage	Temp Range (°C)	Package	Status	Packaging Format
74ACT157SCX	onsemi	4 x 2:1	24 / 24	4.5-5.5V	-40 to 85	16-SOIC	Obsolete	Bulk
MC74ACT157DR2G	onsemi	4 x 2:1	24 / 24	4.5-5.5V	-40 to 85	16-SOIC	Active	Tape & Reel
MC74ACT157DG	onsemi	4 x 2:1	24 / 24	4.5-5.5V	-40 to 85	16-SOIC	Active	Tube
MC74ACT257DR2G	onsemi	4 x 2:1	24 / 24	4.5-5.5V	-40 to 85	16-SOIC	Active	Tape & Reel
74AHCT157D,118	Nexperia USA Inc.	4 x 2:1	8 / 8	4.5-5.5V	-40 to 125	16-SOIC	Active	Tape & Reel
CD74ACT157M	Harris Corporation	4 x 2:1	24 / 24	4.5-5.5V	-55 to 125	16-SOIC	Obsolete	Tube
CD74ACT157M96	Texas Instruments	4 x 2:1	24 / 24	4.5-5.5V	-55 to 125	16-SOIC	Active	Tape & Reel

Engineering Selection Recommendations

Preferred Primary Substitute: MC74ACT157DR2G (onsemi)

This part provides direct electrical and functional equivalence to the 74ACT157SCX with active product status from the original manufacturer. The Tape & Reel packaging format supports automated assembly processes. RoHS3 compliance and unlimited moisture sensitivity rating (MSL 1) meet modern manufacturing standards.

Alternative Active Substitute: CD74ACT157M96 (Texas Instruments)

This part maintains identical output current specifications (24mA/24mA) and supply voltage range with extended operating temperature range (-55°C to 125°C). Active product status and RoHS3 compliance ensure long-term availability. Tape & Reel packaging supports production requirements.

Lower Current Alternative: 74AHCT157D,118 (Nexperia USA Inc.)

This part provides equivalent circuit topology and package form factor with reduced output current (8mA/8mA). Selection requires verification that application load requirements do not exceed 8mA per output. Extended temperature range (-40°C to 125°C) and active status support new designs. Use only when output current reduction is acceptable.

Not Recommended: CD74ACT157M (Harris Corporation)

Obsolete product status limits availability and supply chain reliability. RoHS non-compliance may conflict with modern procurement requirements.

Frequently Asked Questions (FAQ)

Q: Can MC74ACT157DR2G directly replace 74ACT157SCX in existing designs?

A: Yes. MC74ACT157DR2G provides identical electrical specifications, circuit configuration, and package form factor. The primary difference is packaging format (Tape & Reel vs. bulk) and active product status. No design modifications are required.

Q: What is the difference between MC74ACT157DR2G and MC74ACT257DR2G?

A: Both parts share identical electrical parameters and package specifications. The base part number difference (74ACT157 vs. 74ACT257) indicates different internal circuit configurations or pinout arrangements. Design verification is required before substitution to confirm functional compatibility.

Q: Why does 74AHCT157D,118 have lower output current (8mA vs. 24mA)?

A: The 74AHCT series uses advanced CMOS technology with reduced power consumption compared to the 74ACT series. Output current capability is proportionally reduced. This part is suitable only for applications where load current does not exceed 8mA per output.

Q: Are all substitute parts RoHS compliant?

A: CD74ACT157M (Harris Corporation) is RoHS non-compliant. All other listed substitutes are RoHS3 compliant. Verify compliance requirements for your application before selection.

Q: What is the significance of packaging format (Tape & Reel vs. Tube)?

A: Tape & Reel packaging is optimized for automated pick-and-place assembly and high-volume production. Tube packaging is suitable for manual assembly or lower-volume applications. Both formats contain identical components; selection depends on assembly process requirements.

Q: Can I use CD74ACT157M96 in applications requiring -40°C minimum temperature operation?

A: Yes. CD74ACT157M96 operates from -55°C to 125°C, exceeding the -40°C to 85°C range of the original 74ACT157SCX. This part is suitable for extended temperature range applications.

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