ST4-24B18 Equivalent & Substitute Parts

Part Overview

The ST4-24B18 is a laminated core power transformer manufactured by Pulse Electronics, rated at 6VA with dual secondary windings capable of parallel (12V, 500mA) or series (24V, 250mA) output configurations. The primary winding accepts 115V single-phase input. This through-hole mounted component is designed for PC pin termination and maintains 2500Vrms isolation between primary and secondary circuits. The part is currently active in production with RoHS compliance and unlimited moisture sensitivity rating (MSL 1).

Equivalent substitute parts are identified when manufacturers discontinue production lines, when inventory constraints require alternative sourcing, or when design flexibility permits component interchangeability within specified electrical and mechanical tolerances.

Substiute Parts

ST4-24B18

Pulse ElectronicsIn Stock: 1105ST4-24B18 Datasheet

Current PartRFQ

3FS-424

TamuraIn Stock: 9173FS-424 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

The 3FS-424 manufactured by Tamura qualifies as a direct substitute for the ST4-24B18 based on the following critical parameters:

• Identical power rating (6VA)
• Matching primary voltage specification (115V)
• Identical secondary voltage configurations (parallel 12V, series 24V)
• Matching output current ratings (parallel 500mA, series 250mA)
• Identical core type (laminated)
• Matching mounting method (through hole)
• Identical termination style (PC pin)
• Equivalent isolation voltage (2500Vrms)
• Equivalent RoHS compliance status
• Equivalent MSL rating (1 - Unlimited)

Physical dimensions show minor variations within acceptable tolerances for through-hole PCB mounting applications.

Parameter Comparison

Engineering Selection Recommendations

Both the ST4-24B18 and 3FS-424 are active production components with equivalent electrical specifications and regulatory compliance. Selection between these parts should be based on:

• Inventory availability and lead time requirements
• PCB layout constraints, as the 3FS-424 exhibits slightly larger width and height dimensions (1.56mm and 1.28mm respectively)
• Packaging format preference (ST4-24B18 supplied in standard packaging; 3FS-424 supplied in tube packaging)
• Supplier relationship and pricing structure
• Design documentation and qualification history with each manufacturer

Both transformers satisfy identical electrical performance requirements and regulatory obligations (RoHS, REACH unaffected, EAR99 classification).

Frequently Asked Questions (FAQ)

Q: Can the 3FS-424 be used as a direct replacement for the ST4-24B18 on existing PCBs?

A: Electrical substitution is valid. Physical substitution requires verification of PCB footprint clearance, as the 3FS-424 is 1.56mm wider and 1.28mm taller than the ST4-24B18. Confirm mounting hole spacing and surrounding component placement before implementation.

Q: Are there differences in transformer efficiency or thermal performance between these parts?

A: Efficiency and thermal characteristics are not provided in the component specifications. Both transformers carry identical 6VA power ratings and isolation voltage specifications. Thermal performance validation requires manufacturer datasheets or thermal testing.

Q: Do both transformers support the same winding configurations?

A: Yes. Both parts feature dual secondary windings with identical parallel (12V, 500mA) and series (24V, 250mA) output configurations. Primary winding configuration is single-phase 115V input for both.

Q: What is the significance of the MSL 1 rating?

A: MSL 1 (Unlimited) indicates both transformers have unlimited shelf life and require no special moisture control during storage or handling. This classification applies to components with inherently low moisture sensitivity.

Q: Are there any compliance or certification differences?

A: Both transformers are RoHS compliant, REACH unaffected, and classified as EAR99 for export control purposes. Regulatory status is equivalent.