FSQ500N Equivalent & Substitute Parts

Part Overview

The FSQ500N is an offline switch flyback converter IC manufactured by onsemi, designed for isolated power management applications. This 8-DIP through-hole component operates at 130kHz switching frequency with 6.5W output power capability and integrated current limiting, overload, and over-temperature protection. The FSQ500N is classified as obsolete, making identification of functionally equivalent substitute parts essential for design continuity and procurement planning.

Substiute Parts

FSQ500N

onsemiIn Stock: 1529FSQ500N Datasheet

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FSQ500L

onsemiIn Stock: 5183FSQ500L Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FSQ500N are identified based on strict electrical and mechanical compatibility criteria. The primary substitute, FSQ500L, shares the following critical parameters with the FSQ500N:

• Identical manufacturer (onsemi) and series (FPS™)
• Identical topology (Flyback) and output isolation (Isolated)
• Identical voltage breakdown rating (700V)
• Identical supply voltage range (5V ~ 10V)
• Identical switching frequency (130kHz)
• Identical startup voltage (6V)
• Identical duty cycle (60%)
• Identical fault protection features (Current Limiting, Over Load, Over Temperature)
• Identical operating temperature range (-40°C ~ 85°C)
• Identical base product number (FSQ500)

The FSQ500L differs in packaging (SOT-223-4 surface mount versus 8-DIP through hole) and power rating (3W versus 6.5W). These differences require circuit board redesign and thermal management evaluation.

Parameter Comparison

Engineering Selection Recommendations

Both the FSQ500N and FSQ500L are classified as obsolete products. Selection between these parts depends on application power requirements and board layout constraints.

The FSQ500N operates at 6.5W maximum power output with through-hole 8-DIP packaging suitable for conventional PCB assembly methods. The FSQ500L operates at 3W maximum power output with surface-mount SOT-223-4 packaging, offering reduced board footprint but requiring SMT assembly capability.

The FSQ500L includes soft start control functionality not specified for the FSQ500N. Both parts maintain identical electrical specifications for topology, isolation, voltage ratings, switching frequency, and protection features.

Compliance certifications are equivalent: both parts are REACH Unaffected and classified under ECCN EAR99 and HTSUS 8542.39.0001.

Frequently Asked Questions (FAQ)

Q: Can FSQ500L directly replace FSQ500N in existing designs?

A: Electrical substitution is possible only if application power requirements do not exceed 3W. Mechanical substitution requires PCB redesign due to different package types (8-DIP through-hole versus SOT-223-4 surface mount) and different pin configurations.

Q: What are the key electrical parameters that must match for substitution?

A: Critical matching parameters include topology (Flyback), output isolation (Isolated), voltage breakdown rating (700V), supply voltage range (5V ~ 10V), switching frequency (130kHz), startup voltage (6V), duty cycle (60%), and fault protection features (Current Limiting, Over Load, Over Temperature).

Q: How does the power rating difference affect substitution?

A: The FSQ500N is rated for 6.5W output power while the FSQ500L is rated for 3W. Applications requiring power output exceeding 3W cannot use the FSQ500L as a substitute. Thermal management and transformer design must be re-evaluated for lower power ratings.

Q: Are there packaging considerations for substitution?

A: Yes. The FSQ500N uses through-hole 8-DIP packaging (0.300", 7.62mm) for conventional PCB assembly. The FSQ500L uses surface-mount SOT-223-4 packaging. Substitution requires complete PCB redesign and different assembly processes.

Q: What is the significance of the soft start feature in FSQ500L?

A: The FSQ500L includes soft start control functionality. This feature is not specified for the FSQ500N. Soft start reduces inrush current during power-up, which may affect circuit behavior in applications sensitive to startup transients.

Q: Are both parts still available for procurement?

A: Both the FSQ500N and FSQ500L are classified as obsolete. However, inventory availability may vary. The FSQ500L shows higher current stock levels (5100 pcs) compared to FSQ500N (1450 pcs) at the time of this reference.