ROX1SF3K9 Equivalent & Substitute Parts

Part Overview

The ROX1SF3K9 is a 3.9 kOhms ±1% 1W through-hole axial resistor manufactured by TE Connectivity Passive Product. This metal oxide film resistor features flame-proof and pulse-withstanding characteristics, designed for applications requiring safety-rated components. The part is classified as obsolete, necessitating identification of functionally equivalent active alternatives to maintain supply chain continuity and support ongoing production requirements.

Substiute Parts

ROX1SF3K9

TE Connectivity Passive ProductIn Stock: 1064ROX1SF3K9 Datasheet

Current PartRFQ

FMF1WSFRF52-3K9

YAGEOIn Stock: 1010FMF1WSFRF52-3K9 Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the ROX1SF3K9 is based on electrical and mechanical parameter equivalence within the following criteria:

Critical Matching Parameters:

• Resistance value: 3.9 kOhms
• Tolerance: ±1%
• Power rating: 1W
• Package configuration: Axial through-hole
• Termination count: 2
• Safety features: Flame proof and safety-rated construction

Acceptable Variation Parameters:

• Composition: Metal oxide film to metal film transition (both suitable for 1W axial applications)
• Temperature coefficient: Substitute exhibits improved stability (±100ppm/°C vs. ±350ppm/°C)
• Operating temperature upper limit: Substitute supports extended range (-55°C to 155°C vs. -55°C to 130°C)
• Physical dimensions: Minor variations within axial package standard (3.50mm x 10.00mm vs. 3.30mm x 9.00mm)

The FMF1WSFRF52-3K9 from YAGEO satisfies all critical electrical and mechanical requirements for direct substitution.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: FMF1WSFRF52-3K9 (YAGEO)

The FMF1WSFRF52-3K9 is the direct functional equivalent for the obsolete ROX1SF3K9. Selection is based on the following engineering factors:

Product Status: The substitute part maintains active production status, ensuring long-term availability and supply chain reliability compared to the obsolete main part.

Electrical Equivalence: Both parts deliver identical resistance (3.9 kOhms), tolerance (±1%), and power rating (1W). The substitute's metal film composition provides improved temperature coefficient performance (±100ppm/°C versus ±350ppm/°C), resulting in superior frequency stability and reduced drift over operating temperature ranges.

Mechanical Compatibility: Axial package configuration and two-terminal design ensure direct board-level compatibility. Physical dimension variations (3.30mm x 9.00mm versus 3.50mm x 10.00mm) fall within standard axial resistor tolerances and do not affect PCB layout or mounting procedures.

Thermal Performance: The substitute supports an extended operating temperature range (-55°C to 155°C versus -55°C to 130°C), providing additional margin for high-temperature applications.

Regulatory Compliance: Both parts share identical ECCN (EAR99) and HTSUS (8533.21.0090) classifications. The substitute carries ROHS3 compliance and REACH unaffected status, meeting current environmental and regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can the FMF1WSFRF52-3K9 be used as a direct replacement for the ROX1SF3K9 without circuit modification?

A: Yes. Both parts are 3.9 kOhms ±1% 1W axial resistors with identical electrical specifications and two-terminal axial package configuration. No circuit modifications are required for substitution.

Q: What is the difference between metal oxide film and metal film composition?

A: Metal oxide film resistors (ROX1SF3K9) and metal film resistors (FMF1WSFRF52-3K9) both operate at 1W with ±1% tolerance in this application. The metal film composition of the substitute provides superior temperature coefficient stability (±100ppm/°C versus ±350ppm/°C), resulting in reduced resistance drift across temperature variations.

Q: Are there physical dimension differences that affect PCB layout?

A: The substitute measures 3.30mm diameter x 9.00mm length compared to the main part's 3.50mm x 10.00mm. These variations are within standard axial resistor package tolerances and do not require PCB layout modifications. Both parts use identical two-terminal axial configuration.

Q: Does the substitute support the same temperature range?

A: The substitute supports an extended operating range of -55°C to 155°C compared to the main part's -55°C to 130°C. This provides additional thermal margin for high-temperature applications while maintaining full compatibility at the main part's specified range.

Q: What packaging format is available for the substitute?

A: The FMF1WSFRF52-3K9 is supplied in Tape & Reel (TR) format, suitable for automated assembly processes. The main part's original packaging format is not specified in available documentation.

Q: Are both parts RoHS compliant?

A: The substitute (FMF1WSFRF52-3K9) carries ROHS3 compliance certification. RoHS status for the obsolete main part (ROX1SF3K9) is not documented in available specifications.

Q: What is the inventory status for the substitute part?

A: The FMF1WSFRF52-3K9 maintains active production status with 952 pieces available in current inventory as new original stock.