FST3253QSCX Equivalent & Substitute Parts

Part Overview

The FST3253QSCX is a 2 x 4:1 Multiplexer/Demultiplexer logic IC manufactured by onsemi in a 16-QSOP surface mount package. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production support. The FST3253QSCX operates with single supply voltage between 4V and 5.5V across an operating temperature range of -40°C to 85°C, serving applications requiring signal routing and multiplexing functionality in logic circuits.

Substiute Parts

FST3253QSCX

onsemiIn Stock: 4221FST3253QSCX Datasheet

Current PartRFQ

SN74CBT3253DBQR

Texas InstrumentsIn Stock: 5815SN74CBT3253DBQR Datasheet

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CBT3253ADS,118

Nexperia USA Inc.In Stock: 750CBT3253ADS,118 Datasheet

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PI5C3253QE

Diodes IncorporatedIn Stock: 2848PI5C3253QE Datasheet

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PI5C3253QEX

Diodes IncorporatedIn Stock: 36663PI5C3253QEX Datasheet

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QS3253QG

Renesas Electronics CorporationIn Stock: 3892QS3253QG Datasheet

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QS3253QG8

Renesas Electronics CorporationIn Stock: 2672QS3253QG8 Datasheet

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SN74CBT3253CDBQR

Texas InstrumentsIn Stock: 2287SN74CBT3253CDBQR Datasheet

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SN74CBT3253CDBR

Texas InstrumentsIn Stock: 2090SN74CBT3253CDBR Datasheet

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SN74CBT3253DBR

Texas InstrumentsIn Stock: 6381SN74CBT3253DBR Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the FST3253QSCX is determined by strict equivalence in the following parameters:

• Circuit configuration: 2 x 4:1 multiplexer/demultiplexer topology
• Independent circuits: 1
• Mounting type: Surface mount
• Operating temperature range: -40°C to 85°C
• Voltage supply source: Single supply operation
• Package type: 16-pin SSOP/QSOP variants with 0.154" width (3.90mm)

Substitute parts must maintain compatibility across these core electrical and mechanical specifications. Voltage supply ranges may vary within acceptable tolerances (4V to 5.5V for FST3253QSCX; 4.5V to 5.5V or 4.75V to 5.25V for alternatives), provided the operating envelope encompasses the intended application requirements.

Parameter Comparison

Engineering Selection Recommendations

For new designs and production applications, active status parts are preferred over last-time-buy or obsolete designations. Among the available substitutes, the following offer optimal long-term availability and compliance:

CBT3253ADS,118 (Nexperia) provides active product status with ROHS3 compliance and unlimited moisture sensitivity rating, making it suitable for standard manufacturing environments. This part maintains the 4.5V to 5.5V supply range and 16-SSOP package footprint compatible with FST3253QSCX designs.

PI5C3253QE and PI5C3253QEX (Diodes Incorporated) offer active status with ROHS3 compliance and unlimited MSL rating. The PI5C3253QEX variant in tape-and-reel packaging provides higher inventory availability (36,600 units) for volume production requirements. Both operate within the 4.75V to 5.25V supply range.

QS3253QG and QS3253QG8 (Renesas Electronics) maintain active product status with ROHS3 compliance and unlimited MSL. These parts operate within the 4.75V to 5.25V supply envelope and provide established supply chain presence.

SN74CBT3253CDBQR (Texas Instruments) is active with ROHS3 compliance, though moisture sensitivity is rated at 2 (1 Year), requiring controlled storage conditions. This part operates within the 4.5V to 5.5V range and offers the broadest voltage tolerance envelope.

Package width variations exist: SN74CBT3253CDBR and SN74CBT3253DBR feature 16-SSOP packages with 5.30mm width (0.209"), differing from the standard 3.90mm width. PCB layout compatibility must be verified before selection.

Frequently Asked Questions (FAQ)

Q: Can FST3253QSCX be directly replaced with any of these substitute parts?

A: Direct replacement is possible only when the application voltage supply and PCB layout accommodate the selected substitute. All listed parts maintain the 2 x 4:1 multiplexer/demultiplexer circuit configuration and -40°C to 85°C operating temperature range. Voltage supply ranges vary: FST3253QSCX operates 4V to 5.5V, while most substitutes operate 4.5V to 5.5V or 4.75V to 5.25V. Verify your application's supply voltage falls within the substitute part's specified range.

Q: What is the difference between 16-SSOP packages with 3.90mm and 5.30mm widths?

A: Both are 16-pin SSOP packages with identical pin pitch and electrical characteristics. The width difference (3.90mm versus 5.30mm) affects PCB footprint dimensions. Parts with 3.90mm width (FST3253QSCX, SN74CBT3253DBQR, CBT3253ADS,118, PI5C3253QE, PI5C3253QEX, QS3253QG, QS3253QG8, SN74CBT3253CDBQR) are mechanically interchangeable. Parts with 5.30mm width (SN74CBT3253CDBR, SN74CBT3253DBR) require PCB layout verification before substitution.

Q: Which substitute offers the best long-term availability?

A: PI5C3253QEX (Diodes Incorporated) shows the highest current inventory at 36,600 units in tape-and-reel packaging, indicating strong supply chain support. CBT3253ADS,118 (Nexperia) and QS3253QG (Renesas) also maintain active status with substantial inventory levels (736 and 3,880 units respectively).

Q: Are all substitutes ROHS3 compliant?

A: All listed substitute parts carry ROHS3 compliance certification. The original FST3253QSCX does not specify RoHS status. For applications requiring RoHS compliance, any of the listed substitutes satisfy this requirement.

Q: What does Moisture Sensitivity Level (MSL) mean for component selection?

A: MSL indicates the maximum time a component can be exposed to ambient conditions (typically 30°C, 85% relative humidity) before soldering. MSL 1 (Unlimited) allows indefinite storage without special handling. MSL 2 (1 Year) requires controlled storage and limits shelf life to one year. For standard manufacturing, MSL 1 parts (CBT3253ADS,118, PI5C3253QE, PI5C3253QEX, QS3253QG, QS3253QG8, SN74CBT3253CDBR, SN74CBT3253DBR) eliminate moisture-related handling constraints.

Q: Can I use parts with different voltage supply ranges interchangeably?

A: No. The application's power supply voltage must fall within the substitute part's specified range. FST3253QSCX operates 4V to 5.5V. If your circuit supplies 4.2V, substitutes requiring minimum 4.5V (Texas Instruments 74CBT series) are not suitable. Diodes and Renesas parts rated 4.75V to 5.25V require supplies within that narrower window. Verify your application voltage before selection.