STR-W6756 Equivalent & Substitute Parts

Part Overview

The STR-W6756 is an offline switching flyback converter IC manufactured by Sanken Electric USA Inc., designed for isolated power supply applications. This component operates in the 19kHz to 25kHz switching frequency range with a maximum power rating of 240W and supports input voltages from 9.7V to 35V. The part is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing system support and new design considerations where similar performance characteristics are required.

Substiute Parts

STR-W6756

Sanken Electric USA Inc.In Stock: 1198STR-W6756 Datasheet

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TOP249YN

Power IntegrationsIn Stock: 24211TOP249YN Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the STR-W6756 is based on the following critical parameters that define functional equivalence in offline flyback converter applications:

Primary Substitution Criteria:

• Topology: Flyback converter architecture
• Output Isolation: Isolated configuration
• Internal Switch(s): Integrated switching element
• Voltage - Breakdown: Minimum 650V rating
• Voltage - Supply Range: Compatibility with 9.7V to 35V input
• Power Rating: Minimum 240W capability
• Fault Protection: Current limiting, over voltage protection
• Package Compatibility: Through-hole mounting in TO-220 family

The TOP249YN from Power Integrations meets these substitution criteria as an isolated flyback converter with integrated switching, higher breakdown voltage (700V), equivalent power rating (250W), and compatible through-hole TO-220 packaging. While switching frequency differs (66kHz to 132kHz versus 19kHz to 25kHz), this represents a design parameter variation rather than a functional incompatibility, as both operate within the flyback topology framework with equivalent protection features.

Parameter Comparison

Engineering Selection Recommendations

For Existing System Support: The TOP249YN serves as a functional substitute for the obsolete STR-W6756 in applications requiring component replacement. Both devices are RoHS compliant with MSL 1 ratings, ensuring compatibility with standard manufacturing and storage conditions. The TOP249YN provides higher breakdown voltage (700V versus 650V) and extended operating temperature range (-40°C to 150°C versus -20°C to 115°C), offering improved thermal and voltage margin in replacement scenarios.

Design Considerations: The TOP249YN operates at higher switching frequencies (66kHz to 132kHz) compared to the STR-W6756 (19kHz to 25kHz). This frequency difference requires transformer and filter component redesign to maintain equivalent performance. The TOP249YN includes frequency control features and over-temperature protection, whereas the STR-W6756 implements soft start control. Pin configuration differs between TO-220-6 and TO-220-7 packages, necessitating PCB layout modifications.

Product Status Impact: Both parts carry end-of-life designations (Obsolete for STR-W6756; Not For New Designs for TOP249YN), indicating limited long-term availability. For new designs, evaluation of current-generation flyback converter ICs from both manufacturers is recommended to ensure sustained supply chain access.

Frequently Asked Questions (FAQ)

Q: Can the TOP249YN directly replace the STR-W6756 without circuit modifications? A: No. While both are isolated flyback converters with equivalent power ratings, the TOP249YN operates at significantly higher switching frequencies (66kHz to 132kHz versus 19kHz to 25kHz). Transformer design, output filtering, and control loop compensation require redesign. Additionally, the package differs (TO-220-7 versus TO-220-6), requiring PCB layout changes.

Q: What are the key electrical parameters that define substitution compatibility? A: Substitution compatibility is determined by topology (flyback), output isolation (isolated), internal switching capability, breakdown voltage rating (minimum 650V), power rating (minimum 240W), fault protection features (current limiting and over-voltage), and through-hole TO-220 family packaging. Both parts meet these criteria.

Q: How do the fault protection features differ between these parts? A: The STR-W6756 provides current limiting, over-load, and over-voltage protection with soft-start control. The TOP249YN provides current limiting, over-temperature, and over-voltage protection with frequency control. The TOP249YN's over-temperature protection offers additional thermal management capability absent in the STR-W6756.

Q: Are there supply voltage compatibility concerns? A: The STR-W6756 specifies a supply voltage range of 9.7V to 35V. The TOP249YN does not provide explicit supply voltage specifications in the available data. Circuit design validation is necessary to confirm supply voltage compatibility in the target application.

Q: What is the impact of different operating temperature ranges? A: The TOP249YN supports -40°C to 150°C (junction temperature) versus the STR-W6756's -20°C to 115°C (ambient temperature). The TOP249YN provides wider thermal operating margin, beneficial for applications in extreme temperature environments or high-power dissipation scenarios.

Q: Are both parts suitable for new designs? A: No. Both parts carry end-of-life status (STR-W6756 is Obsolete; TOP249YN is Not For New Designs). For new designs, current-generation flyback converter ICs should be evaluated to ensure long-term supply chain availability and access to latest performance improvements.