FSQ0265RLX Equivalent & Substitute Parts

Part Overview

The FSQ0265RLX is an offline switch flyback converter IC manufactured by onsemi, designed for isolated power management applications. This device operates in the FPS™ series with a 55kHz to 67kHz switching frequency and delivers up to 20W of power. The FSQ0265RLX is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Alternative models within the same topology and electrical specifications provide direct functional replacement options.

Substiute Parts

FSQ0265RLX

onsemiIn Stock: 24889FSQ0265RLX Datasheet

Current PartRFQ

NCP1076AAP100G

onsemiIn Stock: 3277NCP1076AAP100G Datasheet

MFR RecommendedRFQ

FSQ0365RLX

onsemiIn Stock: 1433FSQ0365RLX Datasheet

Parametric EquivalentRFQ

FSQ321LX

onsemiIn Stock: 2145FSQ321LX Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FSQ0265RLX are classified based on electrical and mechanical compatibility within the following criteria:

Primary Substitution Parameters:

• Topology: Flyback converter architecture
• Voltage - Breakdown: 650V minimum
• Voltage - Supply Range: 8V ~ 20V compatible range
• Switching Frequency: 55kHz ~ 67kHz operation
• Output Isolation: Isolated configuration
• Internal Switch: Integrated switching element
• Fault Protection: Current Limiting, Over Load, Over Temperature, Over Voltage
• Package Type: 8-LSOP surface mount compatible

Parametric Equivalents (Same Topology, Matching Core Specifications):

• FSQ0365RLX: Identical switching frequency, voltage ratings, and package; increased power rating (25W)
• FSQ321LX: Identical switching frequency, voltage ratings, and package; reduced power rating (12W)

Manufacturer Recommended Substitute (Different Topology, Enhanced Specifications):

• NCP1076AAP100G: Higher switching frequency (100kHz), increased power rating (31W), extended temperature range (-40°C ~ 125°C), different package (7-PDIP through-hole), active product status

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Same Package, Surface Mount): FSQ0365RLX is the preferred parametric equivalent. It maintains identical switching frequency (55kHz ~ 67kHz), voltage specifications (8V ~ 20V supply, 650V breakdown), and 8-LSOP surface mount package. FSQ0365RLX is currently active in production, addressing the obsolescence of FSQ0265RLX. The increased power rating (25W versus 20W) provides design margin without requiring circuit modifications.

For Lower Power Applications: FSQ321LX operates within the same electrical and package specifications but is rated for 12W output. This device is suitable for applications requiring reduced power delivery. FSQ321LX is classified as obsolete; however, it remains available in inventory.

For Enhanced Performance and Extended Temperature Range: NCP1076AAP100G is the manufacturer-recommended substitute offering higher switching frequency (100kHz), increased power capacity (31W), and extended operating temperature range (-40°C ~ 125°C). This device requires through-hole mounting (7-PDIP package) instead of surface mount, necessitating PCB layout modifications. NCP1076AAP100G is active in production and provides superior thermal performance and higher frequency operation for demanding applications.

All substitute options maintain ROHS3 compliance and isolation architecture required for offline flyback converter applications.

Frequently Asked Questions (FAQ)

Q: Can FSQ0365RLX directly replace FSQ0265RLX without circuit modifications? A: Yes. FSQ0365RLX maintains identical switching frequency, voltage supply range, breakdown voltage, and 8-LSOP package configuration. No circuit modifications are required for direct substitution in existing designs.

Q: What is the primary difference between FSQ0265RLX and FSQ0365RLX? A: The primary difference is power rating. FSQ0265RLX is rated for 20W output, while FSQ0365RLX is rated for 25W. Both devices operate at 55kHz ~ 67kHz switching frequency with 8V ~ 20V supply voltage and 650V breakdown voltage.

Q: Why is NCP1076AAP100G classified as a manufacturer-recommended substitute rather than a direct equivalent? A: NCP1076AAP100G operates at 100kHz switching frequency (versus 55kHz ~ 67kHz), uses a 7-PDIP through-hole package (versus 8-LSOP surface mount), and requires PCB layout changes. While it provides enhanced performance specifications, it is not a pin-compatible or package-compatible replacement.

Q: Can NCP1076AAP100G be used in surface mount applications? A: No. NCP1076AAP100G is packaged as 7-PDIP through-hole only. Surface mount applications require FSQ0365RLX or FSQ321LX.

Q: What is the inventory status of substitute parts? A: FSQ0365RLX (1,415 units) and NCP1076AAP100G (3,250 units) are currently in stock with active product status. FSQ321LX (2,100 units) is available but classified as obsolete.

Q: Are all substitute parts ROHS3 compliant? A: Yes. FSQ0365RLX, FSQ321LX, and NCP1076AAP100G are all ROHS3 compliant, matching the compliance status of FSQ0265RLX.

Q: What fault protection features are common across all substitute options? A: All devices provide current limiting, over temperature, and over voltage protection. NCP1076AAP100G additionally includes over power and short circuit protection.