FST3257M Equivalent & Substitute Parts

Part Overview

The FST3257M is a 4 x 2:1 Multiplexer/Demultiplexer logic IC manufactured by onsemi in a 16-SOIC surface mount package. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production support. The FST3257M operates across a single supply voltage range of 3V to 5.5V with an operating temperature range of -40°C to 85°C, serving applications requiring signal multiplexing and demultiplexing functions in logic circuits.

Substiute Parts

FST3257M

onsemiIn Stock: 2126FST3257M Datasheet

Current PartRFQ

74FST3257DR2G

onsemiIn Stock: 443774FST3257DR2G Datasheet

DirectRFQ

CBT3257AD,118

NXP SemiconductorsIn Stock: 46189CBT3257AD,118 Datasheet

SimilarRFQ

SN74CBT3257CD

Texas InstrumentsIn Stock: 1107SN74CBT3257CD Datasheet

SimilarRFQ

SN74CBT3257CDR

Texas InstrumentsIn Stock: 2314SN74CBT3257CDR Datasheet

SimilarRFQ

SN74CBT3257D

Texas InstrumentsIn Stock: 2177SN74CBT3257D Datasheet

SimilarRFQ

SN74CBT3257DR

Texas InstrumentsIn Stock: 2629SN74CBT3257DR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FST3257M is determined by strict equivalence across the following critical parameters:

• Circuit configuration: 4 x 2:1 multiplexer/demultiplexer topology
• Package type: 16-SOIC surface mount form factor
• Mounting compatibility: Surface mount technology
• Operating temperature range: -40°C to 85°C minimum
• Moisture sensitivity: MSL 1 classification
• Supply voltage compatibility: Minimum 3V to 5.5V range support

Substitute parts must maintain identical functional architecture and physical packaging to ensure direct replacement capability. The following parts meet these substitution criteria and are grouped by manufacturer and product status.

Parameter Comparison

Engineering Selection Recommendations

For new designs, active product status parts are preferred: SN74CBT3257CD and SN74CBT3257CDR from Texas Instruments, and CBT3257AD,118 from NXP Semiconductors. These parts maintain full production support and long-term availability.

The 74FST3257DR2G from onsemi is classified as Last Time Buy and remains a direct onsemi-family substitute with ROHS3 compliance, suitable for designs requiring manufacturer continuity within the onsemi product line.

SN74CBT3257D and SN74CBT3257DR from Texas Instruments are Last Time Buy status parts. While still available, these should be evaluated against active alternatives for new production commitments.

All substitute parts listed maintain identical 16-SOIC packaging, -40°C to 85°C operating temperature range, and MSL 1 moisture sensitivity classification. Voltage supply range differences (3V minimum for FST3257M versus 4V or 4.5V minimums for substitutes) must be evaluated against specific circuit requirements.

Frequently Asked Questions (FAQ)

Q: Can FST3257M be directly replaced with SN74CBT3257CD?

A: Yes. Both parts share identical 4 x 2:1 circuit configuration, 16-SOIC package, -40°C to 85°C operating temperature, and MSL 1 classification. The SN74CBT3257CD has a minimum supply voltage of 4.5V versus 3V for the FST3257M; verify your circuit operates at 4.5V or higher.

Q: What is the difference between SN74CBT3257CD and SN74CBT3257CDR?

A: Both parts are functionally identical with the same electrical specifications. The primary difference is packaging format: SN74CBT3257CD is supplied in Tube packaging, while SN74CBT3257CDR is supplied in Cut Tape (CT) & Digi-Reel® format. Select based on your procurement and assembly requirements.

Q: Is CBT3257AD,118 compatible with FST3257M applications?

A: Yes. The CBT3257AD,118 maintains the same 4 x 2:1 multiplexer/demultiplexer function, 16-SOIC package, and operating temperature range. The minimum supply voltage is 4.5V; confirm your application operates within this range.

Q: Why do substitute parts have higher minimum supply voltages?

A: The FST3257M supports 3V minimum supply, while most substitutes (74FST3257DR2G at 4V, and Texas Instruments/NXP parts at 4.5V) have higher minimums. This reflects different design generations and process technologies. Select substitutes based on your circuit's actual supply voltage.

Q: Are all listed substitutes ROHS3 compliant?

A: ROHS3 compliance is confirmed for 74FST3257DR2G, SN74CBT3257CD, SN74CBT3257CDR, SN74CBT3257D, and SN74CBT3257DR. CBT3257AD,118 compliance status is not specified in available data.

Q: Which substitute has the longest product lifecycle?

A: SN74CBT3257CD and SN74CBT3257CDR from Texas Instruments are classified as Active products, indicating ongoing production and long-term availability. These are recommended for new designs requiring extended lifecycle support.