ST5-20B15 Equivalent & Substitute Parts

Part Overview

The ST5-20B15 is a 12VA laminated core power transformer manufactured by Pulse Electronics, designed for through-hole mounting applications. This transformer features a single primary winding at 115V and dual secondary windings capable of parallel (10V, 1.2A) or series (20V, 600mA) configurations. The part is currently active in production with RoHS compliance and unlimited moisture sensitivity rating, making it suitable for industrial and commercial power supply applications where equivalent alternatives may be required due to inventory availability, lead time considerations, or design flexibility.

Substiute Parts

ST5-20B15

Pulse ElectronicsIn Stock: 875ST5-20B15 Datasheet

Current PartRFQ

3FS-520

TamuraIn Stock: 13253FS-520 Datasheet

DirectRFQ

F20-600-C2

Triad MagneticsIn Stock: 1113F20-600-C2 Datasheet

DirectRFQ

ST-5-20

Signal TransformerIn Stock: 1007ST-5-20 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the ST5-20B15 are qualified based on electrical and mechanical parameter equivalence. The following criteria determine substitutability:

Electrical Parameters (Critical):

• Primary voltage: 115V
• Secondary voltage configuration: Parallel 10V, Series 20V
• Secondary current capacity: Parallel 1.2A, Series 600mA
• Power rating: 12VA
• Isolation voltage: 2500Vrms
• Core type: Laminated
• Winding configuration: Single primary, dual secondary, no center tap

Mechanical Parameters (Critical):

• Mounting type: Through hole
• Termination style: PC pin
• Physical dimensions within tolerance range
• Height seated (maximum)

Compliance Parameters:

• RoHS compliance status
• ECCN and HTSUS classifications

All three substitute parts (3FS-520, F20-600-C2, ST-5-20) meet these electrical and mechanical requirements and are therefore direct equivalents for the ST5-20B15.

Parameter Comparison

Engineering Selection Recommendations

All three substitute parts are functionally equivalent to the ST5-20B15 and meet the same electrical and mechanical specifications. Selection among these alternatives should be based on the following factors:

Compliance Considerations: The ST5-20B15 carries RoHS compliance status. The F20-600-C2 and ST-5-20 are ROHS3 compliant, representing a more recent compliance standard. All parts are EAR99 classified and share the same HTSUS code, indicating equivalent regulatory treatment.

Physical Fit: Dimensional variations exist within the substitute group. The 3FS-520 has the largest footprint (48.50mm L × 41.52mm W × 38.00mm H), while the F20-600-C2 offers the most compact height (36.50mm). The ST-5-20 and original ST5-20B15 are dimensionally similar. PCB layout constraints should determine selection if space is limited.

Availability and Packaging: All parts are currently in active production with substantial inventory. Packaging differs: 3FS-520 and F20-600-C2 are supplied in tubes, while ST-5-20 is supplied in boxes. Procurement volume and handling requirements may influence packaging preference.

Frequently Asked Questions (FAQ)

Q: Can the 3FS-520, F20-600-C2, and ST-5-20 be used interchangeably with the ST5-20B15?

A: Yes. All three parts meet identical electrical specifications (12VA, 115V primary, 10V/20V secondary, 1.2A/600mA output, 2500Vrms isolation) and share the same mounting type (through hole) and termination style (PC pin). They are direct functional equivalents.

Q: Are there dimensional differences that affect PCB design?

A: Yes. The 3FS-520 is slightly larger (48.50mm L × 41.52mm W × 38.00mm H) compared to the ST5-20B15 (47.24mm L × 39.62mm W × 36.58mm H). The F20-600-C2 and ST-5-20 are dimensionally closer to the original. If PCB layout is constrained, verify mounting hole spacing and clearance requirements before substitution.

Q: Do all substitute parts meet the same compliance standards?

A: All parts are RoHS compliant and EAR99 classified with identical HTSUS codes. The F20-600-C2 and ST-5-20 carry ROHS3 compliance, which is a more recent standard than the RoHS compliance of the ST5-20B15. This represents an upgrade in compliance status.

Q: What is the difference between parallel and series secondary configurations?

A: The dual secondary windings can be connected in parallel (10V at 1.2A maximum) or series (20V at 600mA maximum). All substitute parts support both configurations identically to the ST5-20B15.

Q: Are there any isolation or safety rating differences?

A: No. All parts maintain 2500Vrms isolation voltage, meeting the same safety requirements for primary-to-secondary isolation.

Q: How do packaging options affect component handling?

A: The 3FS-520 and F20-600-C2 are supplied in tubes, which provide protection during automated assembly. The ST-5-20 is supplied in boxes. Tube packaging is generally preferred for high-volume pick-and-place operations, while box packaging may be suitable for manual assembly or lower-volume applications.