FSL538APG Equivalent & Substitute Parts

Part Overview

The FSL538APG is an offline switch flyback converter IC manufactured by onsemi, designed for power management applications requiring isolated DC-DC conversion. This 7-PDIP through-hole component operates at 100kHz switching frequency with 25W power handling capability and comprehensive fault protection including current limiting, overload, overvoltage, and overtemperature protection.

The FSL538APG is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support legacy system maintenance and repairs.

Substiute Parts

FSL538APG

onsemiIn Stock: 1019FSL538APG Datasheet

Current PartRFQ

FSL518APG

onsemiIn Stock: 3978FSL518APG Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FSL538APG are determined by matching the following critical parameters:

• Topology: Flyback converter architecture
• Voltage - Breakdown: 800V rating
• Voltage - Start Up: 16V threshold
• Frequency - Switching: 100kHz operation
• Fault Protection: Current Limiting, Over Load, Over Power, Over Temperature, Over Voltage
• Control Features: EN and Soft Start functionality
• Operating Temperature Range: -40°C ~ 125°C (TJ)
• Package / Case: 8-DIP (0.300", 7.62mm), 7 Leads
• Mounting Type: Through Hole

The FSL518APG meets these core substitution criteria. Variations in power rating (17W vs 25W) represent the primary difference and must be evaluated against specific application requirements.

Parameter Comparison

Engineering Selection Recommendations

Both the FSL538APG and FSL518APG are obsolete products from onsemi. Selection between these parts depends on application power requirements:

The FSL538APG is rated for 25W operation and should be selected for applications requiring the full 25W power capacity.

The FSL518APG is rated for 17W operation and is suitable for applications with power requirements at or below 17W. This part offers higher current inventory availability (3937 Pcs vs 977 Pcs).

Both parts maintain identical electrical characteristics across voltage ratings, switching frequency, fault protection, control features, and operating temperature range. Both are ROHS3 compliant and carry identical package specifications, enabling direct mechanical and electrical substitution within the specified power envelope.

Frequently Asked Questions (FAQ)

Q: Can FSL518APG replace FSL538APG in all applications?

A: FSL518APG can replace FSL538APG only in applications where the power requirement does not exceed 17W. The FSL518APG is rated for 17W maximum, while the FSL538APG is rated for 25W. Applications requiring power output above 17W must use the FSL538APG.

Q: Are the package dimensions identical between these parts?

A: Yes. Both FSL538APG and FSL518APG use the 8-DIP (0.300", 7.62mm) package with 7 leads and through-hole mounting. They are mechanically interchangeable on PCBs designed for this footprint.

Q: Do these parts have identical control features?

A: Yes. Both parts include EN (enable) and Soft Start control features, along with identical fault protection: Current Limiting, Over Load, Over Power, Over Temperature, and Over Voltage protection.

Q: What is the operating temperature range for both parts?

A: Both the FSL538APG and FSL518APG operate across -40°C to 125°C junction temperature (TJ).

Q: Are both parts RoHS compliant?

A: Yes. Both FSL538APG and FSL518APG are ROHS3 compliant.

Q: Why are both parts classified as obsolete?

A: Both the FSL538APG and FSL518APG are obsolete products. Current inventory remains available from authorized distributors, but long-term availability is not guaranteed. For new designs, evaluation of current-generation onsemi offline switch flyback converters is recommended.