FST3345MTC Equivalent & Substitute Parts

Part Overview

The FST3345MTC is an 8 x 1:1 bus switch logic IC manufactured by onsemi in a 20-TSSOP package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The FST3345MTC operates with a single supply voltage between 4V and 5.5V and maintains an operating temperature range of -40°C to 85°C. Identifying compatible alternatives ensures design continuity and supply chain flexibility.

Substiute Parts

FST3345MTC

onsemiIn Stock: 20661FST3345MTC Datasheet

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SN74CBT3345CDBQR

Texas InstrumentsIn Stock: 813SN74CBT3345CDBQR Datasheet

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SN74CBT3345CPW

Texas InstrumentsIn Stock: 1608SN74CBT3345CPW Datasheet

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SN74CBT3345CPWR

Texas InstrumentsIn Stock: 3736SN74CBT3345CPWR Datasheet

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SN74CBT3345DGVR

Texas InstrumentsIn Stock: 4860SN74CBT3345DGVR Datasheet

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SN74CBT3345PW

Texas InstrumentsIn Stock: 1993SN74CBT3345PW Datasheet

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SN74CBT3345PWR

Texas InstrumentsIn Stock: 2320SN74CBT3345PWR Datasheet

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SN74CBT3245APW

Texas InstrumentsIn Stock: 2236SN74CBT3245APW Datasheet

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SN74CBT3245CPW

Texas InstrumentsIn Stock: 2688SN74CBT3245CPW Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the FST3345MTC is determined by strict alignment of the following electrical and mechanical parameters:

• Circuit configuration: 8 x 1:1 bus switch topology
• Independent circuits: 1
• Voltage supply source: Single supply operation
• Voltage supply range: Minimum 4V to 5.5V maximum
• Operating temperature range: -40°C to 85°C
• Mounting type: Surface mount
• Package type: 20-TSSOP or compatible 20-pin packages with equivalent pinout and physical dimensions

Substitute parts are grouped into two categories:

Direct Substitutes (Same Package - 20-TSSOP): Parts maintaining identical package specifications and pinout compatibility with the FST3345MTC.

Parametric Equivalents (Alternative Packages): Parts with equivalent electrical specifications but different package types (20-SSOP, 20-TVSOP) that may require PCB layout modifications.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation - Direct Substitutes (20-TSSOP Package):

SN74CBT3345CPWR and SN74CBT3345CPW are the preferred direct substitutes for FST3345MTC. Both maintain identical package specifications (20-TSSOP, 0.173" width, 4.40mm) and operate within the required voltage and temperature ranges. SN74CBT3345CPWR carries Active product status with ROHS3 compliance, providing long-term availability and regulatory alignment. SN74CBT3345CPW is also Active status with equivalent compliance. Both parts feature MSL 1 (Unlimited) moisture sensitivity, matching the original component.

Alternative Substitutes (Same Package Family):

SN74CBT3345PWR and SN74CBT3345PW maintain 20-TSSOP packaging and full electrical compatibility but carry Last Time Buy status, indicating limited future availability. These parts remain suitable for designs where procurement windows are not constrained.

Package Variant Alternatives:

SN74CBT3345CDBQR provides equivalent electrical functionality in a 20-SSOP package (0.154" width, 3.90mm). This variant requires PCB layout modification due to reduced package width and carries Active product status with ROHS3 compliance. MSL rating is 2 (1 Year), requiring controlled storage conditions.

SN74CBT3345DGVR operates in a 20-TFSOP package with Active Last Time Buy status. Physical dimensions match the original (0.173" width, 4.40mm), but package type differs, potentially affecting thermal characteristics and PCB routing.

Parametric Equivalent (Extended Voltage Range):

SN74CBT3245CPW and SN74CBT3245APW support the full 4V to 5.5V supply range, matching the FST3345MTC lower voltage limit. Both maintain 20-TSSOP packaging and -40°C to 85°C operating temperature. SN74CBT3245CPW is Active status; SN74CBT3245APW is Last Time Buy. These parts are functionally equivalent but represent a different base product number within the 74CBT series.

Frequently Asked Questions (FAQ)

Q: Can SN74CBT3345CPWR directly replace FST3345MTC without PCB modifications?

A: Yes. SN74CBT3345CPWR maintains identical 20-TSSOP packaging (0.173", 4.40mm width) and pinout compatibility. No PCB layout changes are required. Electrical specifications align within the operating parameters.

Q: What is the difference between SN74CBT3345CPWR and SN74CBT3345CPW?

A: Both parts are electrically identical in 20-TSSOP packaging. The primary difference is packaging format: CPWR is supplied in Tape & Reel (TR) format for automated assembly; CPW is supplied in Tube format for manual handling. Select based on assembly process requirements.

Q: Why does SN74CBT3345CDBQR have a different package width (3.90mm vs 4.40mm)?

A: SN74CBT3345CDBQR uses a 20-SSOP package, which is narrower than the 20-TSSOP standard. This requires PCB footprint redesign and cannot be used as a direct drop-in replacement without layout modifications.

Q: What does "Last Time Buy" product status mean?

A: Last Time Buy indicates the manufacturer has announced end-of-life for that specific part number. Existing inventory may be available, but future production is not planned. For long-term designs, Active status parts (SN74CBT3345CPWR, SN74CBT3345CPW) are recommended.

Q: Is SN74CBT3245CPW compatible with FST3345MTC?

A: SN74CBT3245CPW is a parametric equivalent with identical electrical specifications and 20-TSSOP packaging. It supports the full 4V to 5.5V supply range and -40°C to 85°C operating temperature. It functions as a substitute but represents a different base product number (74CBT3245 vs 74CBT3345).

Q: What is the significance of MSL (Moisture Sensitivity Level) ratings?

A: MSL 1 (Unlimited) indicates the component has no moisture sensitivity restrictions and requires no special storage or handling. MSL 2 (1 Year) requires controlled storage conditions and has a one-year shelf life from the date of manufacture. FST3345MTC and most recommended substitutes carry MSL 1 ratings.

Q: Are all substitute parts ROHS3 compliant?

A: All Texas Instruments SN74CBT series substitutes listed carry ROHS3 compliance. The original FST3345MTC does not specify RoHS status. ROHS3 compliance ensures the parts meet current environmental and regulatory requirements for new designs.