3FS-256 Equivalent & Substitute Parts Reference

Part Overview

The 3FS-256 is a laminated core power transformer manufactured by Tamura, rated at 1.1VA with dual secondary windings. This through-hole mounted component is designed for applications requiring isolated AC power conversion with 115V primary input and configurable secondary output (28V parallel or 56V series). The part maintains Active product status with full RoHS compliance and unlimited moisture sensitivity rating.

Substitute parts are identified to address inventory availability, regional sourcing requirements, or packaging preferences while maintaining electrical and mechanical compatibility within specified tolerances.

Substiute Parts

3FS-256

TamuraIn Stock: 8653FS-256 Datasheet

Current PartRFQ

F56-020

Triad MagneticsIn Stock: 1024F56-020 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 3FS-256 is determined by strict equivalence across the following parameters:

Electrical Parameters (Non-negotiable):

• Power rating: 1.1VA
• Primary voltage: 115V
• Secondary voltage configuration: Parallel 28V and Series 56V capability
• Secondary current capacity: Parallel 40mA minimum, Series 20mA minimum
• Isolation voltage: 2500Vrms
• Winding configuration: Single primary, dual secondary

Mechanical Parameters (Non-negotiable):

• Core type: Laminated
• Mounting: Through hole
• Termination: PC pin

Compliance Parameters (Required):

• RoHS compliance status
• ECCN and HTSUS classification alignment

The F56-020 from Triad Magnetics meets all critical electrical and mechanical parameters. Dimensional variations (length, width, height) fall within acceptable tolerances for through-hole PCB mounting applications and do not affect functional compatibility.

Parameter Comparison

Engineering Selection Recommendations

Primary Part Selection (3FS-256): The 3FS-256 maintains Active product status with 806 units in current inventory. RoHS compliance and EAR99 classification support standard procurement workflows. Tube packaging is suitable for automated assembly environments.

Substitute Part Selection (F56-020): The F56-020 is functionally equivalent across all critical electrical and mechanical parameters. ROHS3 compliance exceeds RoHS requirements. Higher inventory availability (996 units) supports extended lead-time mitigation. Box packaging accommodates manual assembly or kit-based applications. Dimensional differences are negligible for through-hole PCB mounting and do not require design modification.

Selection Criteria:

• Choose 3FS-256 when tube packaging is required for automated pick-and-place operations
• Choose F56-020 when box packaging is acceptable and higher inventory availability is prioritized
• Both parts satisfy identical electrical performance requirements and isolation specifications
• Both parts comply with export control and tariff classifications

Frequently Asked Questions (FAQ)

Q: Can the F56-020 be used as a direct replacement for the 3FS-256 in existing designs?

A: Yes. The F56-020 is electrically and mechanically equivalent. All critical parameters—power rating, voltage levels, current capacity, winding configuration, isolation voltage, and mounting type—are identical. Dimensional variations are within acceptable tolerances for through-hole PCB applications and do not require PCB redesign.

Q: What is the difference in packaging between these parts?

A: The 3FS-256 is supplied in tube packaging, optimized for automated assembly lines. The F56-020 is supplied in box packaging, suitable for manual assembly or component kitting. Packaging does not affect electrical performance or component functionality.

Q: Are both parts RoHS compliant?

A: Yes. The 3FS-256 carries RoHS Compliant status. The F56-020 carries ROHS3 Compliant status, which represents an updated compliance standard. Both satisfy RoHS requirements for lead-free manufacturing.

Q: Do the dimensional differences between these parts affect PCB layout?

A: No. The F56-020 dimensions (34.93mm L × 28.58mm W × 23.80mm H seated) are slightly smaller than the 3FS-256 (35.56mm L × 31.00mm W × 25.40mm H seated). These differences are within standard through-hole component tolerances and do not require PCB footprint modification.

Q: What is the isolation voltage specification, and why is it important?

A: Both parts provide 2500Vrms isolation between primary and secondary windings. This specification ensures safe electrical isolation in applications requiring galvanic separation between input and output circuits, supporting safety compliance in Class 2/3 power supply designs.

Q: Can these transformers be configured for different voltage outputs?

A: Yes. Both the 3FS-256 and F56-020 feature dual secondary windings that support two configurations: parallel connection (28V at 40mA maximum) or series connection (56V at 20mA maximum). Configuration is determined by winding connection at assembly.

Q: Are there any restrictions on export or use of these parts?

A: Both parts are classified as EAR99 under export control regulations and HTSUS 8504.31.4035 for tariff purposes. Standard commercial export procedures apply. No additional licensing is required for standard industrial applications.