SN74S257N Equivalent & Substitute Parts

Part Overview

The SN74S257N is a 4 x 2:1 multiplexer logic integrated circuit manufactured by Texas Instruments in the 74S series. This component is classified as obsolete, with 3225 units currently in stock. The SN74S257N operates as a single-supply logic multiplexer with through-hole 16-DIP packaging, designed for applications requiring signal selection and routing in digital systems. Due to its obsolete status, identifying functionally equivalent substitute parts is necessary for ongoing design support and procurement continuity.

Substiute Parts

SN74S257N

Texas InstrumentsIn Stock: 3285SN74S257N Datasheet

Current PartRFQ

SN74HCT257DR

Texas InstrumentsIn Stock: 3897SN74HCT257DR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74S257N is determined by the following critical parameters:

• Functional Equivalence: Circuit configuration must be 4 x 2:1 multiplexer with 1 independent circuit
• Electrical Compatibility: Voltage supply range, output current specifications, and logic family compatibility
• Mechanical Compatibility: Package type determines board-level integration method
• Compliance Requirements: RoHS and REACH certification status

The SN74HCT257DR qualifies as a manufacturer-recommended substitute based on identical circuit configuration (4 x 2:1 multiplexer), compatible voltage supply range (4.5V ~ 5.5V encompasses the original 4.75V ~ 5.25V specification), and equivalent RoHS3 compliance. The primary difference is packaging format: the substitute uses surface-mount 16-SOIC instead of through-hole 16-DIP, requiring PCB redesign for implementation.

Parameter Comparison

Engineering Selection Recommendations

The SN74HCT257DR is the manufacturer-recommended substitute for the obsolete SN74S257N. Both components maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment. The substitute offers extended operating temperature range (-40°C to 85°C versus 0°C to 70°C), providing broader environmental applicability.

Selection of the SN74HCT257DR requires PCB redesign due to package format change from through-hole DIP to surface-mount SOIC. Output current specifications differ: the substitute provides symmetrical 6mA output capability (high and low) compared to the original's asymmetrical 6.5mA high and 20mA low. Voltage supply compatibility is maintained within the original specification window.

Frequently Asked Questions (FAQ)

Q: Can the SN74HCT257DR directly replace the SN74S257N without PCB modification?

A: No. The SN74HCT257DR uses 16-SOIC surface-mount packaging while the SN74S257N uses 16-DIP through-hole packaging. PCB redesign is required for implementation.

Q: Are the output current specifications compatible between these parts?

A: The specifications differ. The SN74S257N provides 6.5mA output high and 20mA output low. The SN74HCT257DR provides 6mA for both output high and low. Verify that your circuit design accommodates the lower output current of the substitute.

Q: What is the voltage supply compatibility between these parts?

A: The SN74HCT257DR voltage supply range (4.5V ~ 5.5V) encompasses the SN74S257N specification (4.75V ~ 5.25V). Both operate within standard 5V logic supply parameters.

Q: Does the extended temperature range of the SN74HCT257DR affect compatibility?

A: The SN74HCT257DR operates from -40°C to 85°C, exceeding the original 0°C to 70°C range. This provides enhanced environmental capability and does not create compatibility issues for applications within the original temperature specification.

Q: Are both parts compliant with current regulatory requirements?

A: Yes. Both the SN74S257N and SN74HCT257DR are ROHS3 compliant and REACH unaffected, meeting current regulatory standards.

Q: What is the inventory status of the substitute part?

A: The SN74HCT257DR is an active product with 3798 units currently in stock, ensuring procurement availability.