FSTU3257MTCX Equivalent & Substitute Parts

Part Overview

The FSTU3257MTCX is a Multiplexer/Demultiplexer logic IC with 4 x 2:1 circuit configuration manufactured by onsemi in a 16-TSSOP surface mount package. This component is classified as Obsolete, making identification of functional equivalents essential for ongoing system support and component procurement. Substitute parts must maintain identical electrical specifications and compatible packaging to ensure direct replacement capability in existing designs.

Substiute Parts

FSTU3257MTCX

onsemiIn Stock: 1731FSTU3257MTCX Datasheet

Current PartRFQ

74FST3257DTR2G

onsemiIn Stock: 330374FST3257DTR2G Datasheet

Parametric EquivalentRFQ

SN74CBT3257CPWR

Texas InstrumentsIn Stock: 47791SN74CBT3257CPWR Datasheet

DirectRFQ

CBT3257ADS,118

Nexperia USA Inc.In Stock: 1917CBT3257ADS,118 Datasheet

SimilarRFQ

CBT3257APW,118

Nexperia USA Inc.In Stock: 3196CBT3257APW,118 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the FSTU3257MTCX is determined by the following critical parameters:

• Circuit configuration: 4 x 2:1 multiplexer/demultiplexer topology
• Voltage supply range: 4V ~ 5.5V single supply operation
• Operating temperature: -40°C ~ 85°C
• Package type: 16-TSSOP or compatible surface mount package
• Moisture sensitivity: MSL 1 (Unlimited)
• Regulatory compliance: REACH Unaffected, EAR99 classification

Substitute parts are grouped into two categories based on package compatibility:

Direct Package Match (16-TSSOP): Parts maintaining identical 16-TSSOP packaging enable direct PCB-level replacement without layout modification.

Compatible Package Variant (16-SSOP): Parts using 16-SSOP packaging (0.154", 3.90mm Width) provide functional equivalence with minor footprint differences, requiring PCB layout verification.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: SN74CBT3257CPWR (Texas Instruments)

The SN74CBT3257CPWR is the preferred substitute for the obsolete FSTU3257MTCX. This part maintains full electrical and mechanical compatibility with identical 16-TSSOP packaging, matching voltage supply range (4.5V ~ 5.5V encompasses the original 4V ~ 5.5V specification), and operating temperature range. The part holds Active product status with ROHS3 compliance and extensive inventory availability (47,740 pcs), ensuring long-term procurement viability and supply chain stability.

Secondary Recommendation: CBT3257APW,118 (Nexperia USA Inc.)

The CBT3257APW,118 provides direct package compatibility with 16-TSSOP configuration and Active product status. This part is suitable for applications where Nexperia component qualification exists. Voltage supply range (4.5V ~ 5.5V) and operating temperature specifications match the primary recommendation.

Alternative Consideration: 74FST3257DTR2G (onsemi)

The 74FST3257DTR2G maintains onsemi manufacturer continuity with identical 16-TSSOP packaging and voltage/temperature specifications. However, this part carries Last Time Buy status, indicating limited future availability. Selection should prioritize long-term supply chain requirements.

Package Variant: CBT3257ADS,118 (Nexperia USA Inc.)

The CBT3257ADS,118 offers functional equivalence with 16-SSOP packaging (0.154", 3.90mm Width). This variant requires PCB layout verification due to footprint differences from the original 16-TSSOP package. Selection is appropriate only when PCB redesign is feasible.

Frequently Asked Questions (FAQ)

Q: Can the SN74CBT3257CPWR directly replace the FSTU3257MTCX without PCB modification?

A: Yes. The SN74CBT3257CPWR maintains identical 16-TSSOP packaging, pin configuration, and electrical specifications. Direct PCB-level substitution is supported without layout changes.

Q: What is the voltage supply difference between FSTU3257MTCX (4V ~ 5.5V) and substitute parts (4.5V ~ 5.5V)?

A: The substitute parts specify a minimum supply voltage of 4.5V versus the original 4V minimum. For applications operating at 4V to 4.5V, the original part specifications must be verified. Most standard 5V logic applications operate within the 4.5V ~ 5.5V range and are unaffected.

Q: Why is CBT3257ADS,118 listed as a substitute if it uses 16-SSOP packaging instead of 16-TSSOP?

A: The CBT3257ADS,118 provides functional equivalence with identical electrical specifications and circuit configuration. The 16-SSOP package (0.154", 3.90mm Width) differs from 16-TSSOP (0.173", 4.40mm Width), requiring PCB footprint verification. This part is suitable only when PCB redesign is acceptable.

Q: What does "Last Time Buy" status mean for the 74FST3257DTR2G?

A: Last Time Buy indicates the manufacturer has announced end-of-life production. Existing inventory may be available, but future procurement is not guaranteed. For new designs or long-term applications, Active status parts (SN74CBT3257CPWR, CBT3257APW,118, CBT3257ADS,118) are recommended.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed carry ROHS3 Compliant certification. The original FSTU3257MTCX does not specify RoHS status in the provided data.

Q: Can I use CBT3257APW,118 and SN74CBT3257CPWR interchangeably?

A: Yes. Both parts maintain identical 16-TSSOP packaging, 4 x 2:1 circuit configuration, -40°C ~ 85°C operating temperature, and 4.5V ~ 5.5V supply voltage. Selection between these parts depends on manufacturer qualification requirements and inventory availability.