74FST3257MNTWG Equivalent & Substitute Parts

Part Overview

The 74FST3257MNTWG is a Multiplexer/Demultiplexer logic IC with a 4 x 2:1 circuit configuration, manufactured by onsemi in a 16-QFN (2.5x4.6) surface mount package. This component is classified as Last Time Buy, indicating limited future availability. Identifying equivalent and substitute parts is essential for design continuity, long-term supply chain planning, and production scheduling.

Substiute Parts

74FST3257MNTWG

onsemiIn Stock: 1628074FST3257MNTWG Datasheet

Current PartRFQ

74FST3257MN2TWG

onsemiIn Stock: 373674FST3257MN2TWG Datasheet

Parametric EquivalentRFQ

CBT3257ABQ,115

Nexperia USA Inc.In Stock: 2414CBT3257ABQ,115 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 74FST3257MNTWG are identified based on strict parametric equivalence across the following critical criteria:

Functional Equivalence: Circuit type (Multiplexer/Demultiplexer), circuit configuration (4 x 2:1), and independent circuit count (1) must be identical.

Electrical Compatibility: Voltage supply range, operating temperature range, and output characteristics must support the same application requirements.

Physical Compatibility: Package type (16-VFQFN Exposed Pad), package dimensions (2.5x4.6), and mounting type (Surface Mount) must be identical or mechanically compatible.

Regulatory Compliance: RoHS3 compliance, MSL rating, and REACH status must meet or exceed the original part specifications.

Substitutes are grouped into two categories:

Parametric Equivalent: 74FST3257MN2TWG (onsemi) — identical across all electrical and mechanical parameters, differing only in manufacturing date code or tape reel configuration.

Similar Equivalent: CBT3257ABQ,115 (Nexperia USA Inc.) — functionally equivalent with compatible electrical specifications but from a different manufacturer series (74CBT vs. 74FST) and slightly different voltage supply range (4.5V ~ 5.5V vs. 4V ~ 5.5V).

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Preferred): The 74FST3257MN2TWG is the primary parametric equivalent. Both parts are manufactured by onsemi, share identical electrical specifications (4V ~ 5.5V supply, -40°C ~ 85°C operating range), and are packaged in the same 16-VFQFN configuration. Both carry Last Time Buy status, indicating similar lifecycle positioning. This part is suitable for immediate substitution without design modification.

For Alternative Supply (Secondary Option): The CBT3257ABQ,115 from Nexperia USA Inc. is functionally equivalent and maintains Active product status, providing superior long-term availability. The voltage supply range is narrower (4.5V ~ 5.5V vs. 4V ~ 5.5V), which is acceptable for applications operating within the 4.5V ~ 5.5V window. The package designation differs (16-DHVQFN vs. 16-QFN), though both are mechanically compatible 16-pin QFN packages with identical 2.5x4.6 dimensions. All regulatory certifications (ROHS3, MSL 1, REACH Unaffected) are equivalent. This part is suitable for designs requiring extended supply chain security.

Frequently Asked Questions (FAQ)

Q: Can 74FST3257MN2TWG be used as a direct replacement for 74FST3257MNTWG?

A: Yes. Both parts are manufactured by onsemi with identical electrical parameters (4V ~ 5.5V supply, -40°C ~ 85°C operating range), circuit configuration (4 x 2:1 multiplexer/demultiplexer), and package specifications (16-VFQFN, 2.5x4.6 dimensions). No design changes are required.

Q: What is the key difference between the onsemi 74FST series and the Nexperia 74CBT series?

A: Both are logic multiplexer/demultiplexer ICs with identical circuit configurations and compatible electrical characteristics. The primary difference is manufacturer and product status: onsemi 74FST3257 parts are Last Time Buy, while the Nexperia CBT3257ABQ,115 is Active. The Nexperia part has a narrower voltage supply range (4.5V ~ 5.5V vs. 4V ~ 5.5V).

Q: Is the CBT3257ABQ,115 package compatible with the 74FST3257MNTWG footprint?

A: Yes. Both parts use 16-pin QFN packages with identical 2.5x4.6 dimensions and 16-VFQFN Exposed Pad configuration. The package designations differ (16-DHVQFN vs. 16-QFN), but the physical footprint and pin layout are mechanically compatible.

Q: Are all three parts RoHS3 compliant?

A: Yes. The 74FST3257MNTWG, 74FST3257MN2TWG, and CBT3257ABQ,115 are all ROHS3 compliant with MSL 1 (Unlimited) ratings and REACH Unaffected status.

Q: Why is the 74FST3257MNTWG marked as Last Time Buy?

A: Last Time Buy status indicates that onsemi has announced end-of-life for this product line. Existing inventory will be sold until depletion, after which the part will no longer be manufactured. The 74FST3257MN2TWG shares this status. For long-term supply security, the Active Nexperia CBT3257ABQ,115 is recommended.

Q: Can applications designed for 4V ~ 5.5V supply use the CBT3257ABQ,115 with its 4.5V ~ 5.5V range?

A: The CBT3257ABQ,115 is suitable only for applications operating within the 4.5V ~ 5.5V range. Applications requiring operation below 4.5V must use the onsemi 74FST3257 variants, which support 4V ~ 5.5V.