ST5-12B7 Equivalent & Substitute Parts

Part Overview

The ST5-12B7 is a 12VA laminated core power transformer manufactured by Pulse Electronics, designed for through-hole mounting applications. This split bobbin plug-in transformer provides dual secondary windings with configurable output voltage (parallel 6.3V or series 12.6V) and corresponding current ratings. The part is currently active in production with 1047 units in stock. Equivalent and substitute parts are identified when identical electrical specifications and mechanical compatibility are required for component sourcing, inventory management, or supply chain continuity.

Substiute Parts

ST5-12B7

Pulse ElectronicsIn Stock: 1069ST5-12B7 Datasheet

Current PartRFQ

3FS-512

TamuraIn Stock: 10063FS-512 Datasheet

DirectRFQ

F12-1000

Triad MagneticsIn Stock: 882F12-1000 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the ST5-12B7 are qualified based on strict electrical and mechanical parameter matching:

Electrical Equivalence Criteria:

• Primary voltage: 115V
• Secondary voltage configuration: Parallel 6.3V, Series 12.6V
• Output current ratings: Parallel 2A, Series 1A
• Power rating: 12VA
• Isolation voltage: 2500Vrms
• Core type: Laminated
• Winding configuration: Single primary, dual secondary, no center tap

Mechanical Compatibility Criteria:

• Mounting type: Through hole
• Termination style: PC pin
• Physical dimensions within acceptable tolerance ranges
• Height seated maximum: 36.50mm to 38.00mm

Both identified substitutes (3FS-512 and F12-1000) meet all electrical specifications and mechanical mounting requirements, making them direct functional equivalents to the ST5-12B7.

Parameter Comparison

Engineering Selection Recommendations

All three parts—ST5-12B7, 3FS-512, and F12-1000—are active production components with full regulatory compliance. Selection between these equivalents should be based on:

Compliance Considerations:

• ST5-12B7 and 3FS-512 carry RoHS Compliant certification
• F12-1000 carries ROHS3 Compliant certification, representing the latest RoHS standard
• All parts are REACH Unaffected and classified as EAR99 for export control purposes

Availability and Packaging:

• ST5-12B7: 1047 units in stock, split bobbin plug-in series
• 3FS-512: 995 units in stock, supplied in tube packaging, 3FS-5xx series
• F12-1000: 811 units in stock, supplied in box packaging, split pack series with Class 2/3 rating

Physical Dimensions:

• All parts fit within acceptable through-hole mounting envelope
• F12-1000 offers the lowest seated height at 36.50mm
• 3FS-512 has the largest footprint with 48.50mm length and 41.52mm width
• ST5-12B7 and F12-1000 provide the most compact lateral dimensions

Frequently Asked Questions (FAQ)

Q: Can the 3FS-512 directly replace the ST5-12B7 in an existing PCB design?

A: Yes. The 3FS-512 matches all electrical specifications and uses identical through-hole PC pin termination. Physical dimensions are within acceptable tolerance for standard through-hole mounting. Verify PCB footprint clearance, as the 3FS-512 has slightly larger lateral dimensions (48.50mm L × 41.52mm W versus 47.24mm L × 39.62mm W).

Q: What is the difference between the F12-1000 and ST5-12B7 regarding compliance?

A: Both are fully compliant with current regulations. The F12-1000 carries ROHS3 Compliant certification, representing the most recent RoHS standard revision. The ST5-12B7 carries RoHS Compliant certification. Both are REACH Unaffected and EAR99 classified.

Q: Are there any height restrictions when substituting these parts?

A: Height differences are minimal. ST5-12B7 seated height is 36.58mm, F12-1000 is 36.50mm, and 3FS-512 is 38.00mm. If vertical clearance is constrained, F12-1000 or ST5-12B7 are preferred. Verify available board-to-component clearance before final selection.

Q: Do all three parts support both parallel and series secondary winding configurations?

A: Yes. All three transformers provide dual secondary windings with identical voltage and current ratings: parallel 6.3V at 2A or series 12.6V at 1A. Winding configuration is determined by circuit design, not part selection.

Q: What packaging considerations apply when ordering substitutes?

A: ST5-12B7 uses standard through-hole packaging. 3FS-512 is supplied in tube packaging, suitable for automated assembly. F12-1000 is supplied in box packaging. Verify compatibility with receiving and assembly processes before ordering.