FSQ0165RLX Equivalent & Substitute Parts

Part Overview

The FSQ0165RLX is an offline switch flyback converter IC manufactured by onsemi, designed for isolated power management applications. This device operates in the 55kHz to 67kHz switching frequency range with a 15W power rating and includes integrated fault protection for current limiting, overload, over-temperature, and over-voltage conditions. The FSQ0165RLX is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support.

Substiute Parts

FSQ0165RLX

onsemiIn Stock: 40266FSQ0165RLX Datasheet

Current PartRFQ

NCP1076AAP100G

onsemiIn Stock: 3277NCP1076AAP100G Datasheet

MFR RecommendedRFQ

FSQ0265RLX

onsemiIn Stock: 24889FSQ0265RLX Datasheet

Parametric EquivalentRFQ

FSQ0365RLX

onsemiIn Stock: 1433FSQ0365RLX Datasheet

Parametric EquivalentRFQ

FSQ321LX

onsemiIn Stock: 2145FSQ321LX Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the FSQ0165RLX is determined by the following critical parameters: flyback topology, 650V breakdown voltage, 8V to 20V supply voltage range, 55kHz to 67kHz switching frequency, surface mount 8-LSOP package, and integrated fault protection features. Substitute parts must maintain compatibility across these core electrical and mechanical specifications.

The substitute parts are grouped into two categories:

Parametric Equivalents (Same Package, Same Topology): FSQ0265RLX, FSQ0365RLX, and FSQ321LX maintain the identical 8-LSOP surface mount package and flyback topology with matching voltage and frequency specifications. These parts differ primarily in power rating and product status.

Manufacturer Recommended Alternative (Different Package): NCP1076AAP100G represents an active product alternative with enhanced specifications, including higher breakdown voltage (700V), higher power rating (31W), and higher operating temperature range (-40°C to 125°C). This part uses a through-hole 7-PDIP package instead of surface mount, requiring PCB redesign.

Parameter Comparison

Engineering Selection Recommendations

For direct replacement in existing PCB layouts, FSQ0365RLX is the preferred parametric equivalent. It maintains the identical 8-LSOP surface mount package, matching electrical specifications (650V breakdown, 8V-20V supply, 55kHz-67kHz switching), and provides active product status with current availability. FSQ0365RLX offers increased power capacity (25W versus 15W) while maintaining full backward compatibility with the FSQ0165RLX footprint and pinout.

FSQ0265RLX and FSQ321LX are alternative parametric equivalents within the same package family. FSQ0265RLX provides 20W power rating with obsolete status. FSQ321LX offers 12W power rating with obsolete status. Both maintain identical package and electrical specifications but differ in power handling capability.

NCP1076AAP100G represents an active product alternative for designs requiring redesign flexibility. This part offers enhanced specifications including 700V breakdown voltage, 31W power rating, and extended operating temperature range (-40°C to 125°C). However, substitution requires PCB redesign due to the through-hole 7-PDIP package format versus the surface mount 8-LSOP of the original part. The higher switching frequency (100kHz) and lower startup voltage (8.4V) may require transformer and feedback network adjustments.

All substitute parts maintain ROHS3 compliance and onsemi manufacturer origin, ensuring regulatory and supply chain consistency.

Frequently Asked Questions (FAQ)

Q: Can FSQ0365RLX directly replace FSQ0165RLX without PCB modification?

A: Yes. FSQ0365RLX uses the identical 8-LSOP surface mount package with matching pinout and electrical specifications (650V breakdown, 8V-20V supply, 55kHz-67kHz switching frequency). Direct footprint substitution is possible. The increased power rating (25W versus 15W) does not create compatibility issues for applications designed for 15W operation.

Q: What is the primary difference between the FSQ series parametric equivalents?

A: The FSQ0165RLX, FSQ0265RLX, FSQ0365RLX, and FSQ321LX differ in power rating (15W, 20W, 25W, and 12W respectively) while maintaining identical package, topology, voltage specifications, and switching frequency. Selection depends on the power requirement of the target application.

Q: Why does NCP1076AAP100G require PCB redesign?

A: NCP1076AAP100G uses a through-hole 7-PDIP package instead of the surface mount 8-LSOP package of FSQ0165RLX. This package difference requires new PCB layout and assembly process changes. Additionally, the higher switching frequency (100kHz versus 55kHz-67kHz) and lower startup voltage (8.4V versus 12V) may necessitate transformer and feedback circuit adjustments.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. FSQ0265RLX, FSQ0365RLX, FSQ321LX, and NCP1076AAP100G are all ROHS3 compliant, matching the regulatory status of FSQ0165RLX.

Q: Which substitute part has active product status?

A: FSQ0365RLX and NCP1076AAP100G both have active product status. FSQ0265RLX and FSQ321LX are obsolete. For long-term supply assurance, FSQ0365RLX is recommended for surface mount applications and NCP1076AAP100G for through-hole applications.

Q: What fault protection features are included in the substitute parts?

A: FSQ0265RLX, FSQ0365RLX, and FSQ321LX include current limiting, overload, over-temperature, and over-voltage protection. NCP1076AAP100G includes current limiting, over-power, over-temperature, over-voltage, and short-circuit protection, providing enhanced protection coverage.