RNF12FTC121K Equivalent & Substitute Parts

Part Overview

The RNF12FTC121K is a 121 kOhms ±1% 0.5W through-hole axial resistor manufactured by Stackpole Electronics Inc. This metal film resistor features flame retardant coating and safety construction, designed for applications requiring precision resistance values in compact form factors. The part maintains Active product status with 957 units in current inventory. Substitute parts are identified when equivalent electrical specifications, mechanical compatibility, and regulatory compliance can be maintained across alternative manufacturers.

Substiute Parts

RNF12FTC121K

Stackpole Electronics IncIn Stock: 1026RNF12FTC121K Datasheet

Current PartRFQ

CMF55121K00FHEB

Vishay DaleIn Stock: 5701CMF55121K00FHEB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the RNF12FTC121K is determined by strict equivalence across the following parameters:

• Resistance value: 121 kOhms (exact match required)
• Tolerance: ±1% (exact match required)
• Power rating: 0.5W / 1/2W (exact match required)
• Composition: Metal Film (exact match required)
• Package: Axial through-hole (exact match required)
• Temperature coefficient: ±50ppm/°C (exact match required)
• Regulatory compliance: ROHS3 Compliant, REACH Unaffected (minimum requirements)

The CMF55121K00FHEB from Vishay Dale meets all substitution criteria. Both parts share identical electrical specifications and axial package configuration. Mechanical dimensions differ slightly, but both conform to standard axial resistor form factors compatible with equivalent PCB layouts.

Parameter Comparison

Engineering Selection Recommendations

Both the RNF12FTC121K and CMF55121K00FHEB maintain Active product status and full regulatory compliance under ROHS3 and REACH standards. Selection between these parts is based on availability, packaging requirements, and operating environment specifications.

The RNF12FTC121K operates to 155°C maximum, while the CMF55121K00FHEB extends to 175°C. For applications requiring operation above 155°C, the CMF55121K00FHEB provides additional thermal margin. The CMF55121K00FHEB includes moisture-resistant construction, beneficial for high-humidity or sealed enclosure applications.

Packaging format differs: RNF12FTC121K is supplied in Tape & Reel format; CMF55121K00FHEB is supplied in Cut Tape format. Procurement and assembly processes should account for these packaging differences.

Frequently Asked Questions (FAQ)

Q: Can CMF55121K00FHEB replace RNF12FTC121K in all applications?

A: Yes, for applications operating at or below 155°C. The CMF55121K00FHEB supports extended operation to 175°C, making it suitable for higher-temperature environments. All electrical parameters, tolerance, power rating, and package type are equivalent.

Q: What is the difference in physical dimensions between these parts?

A: RNF12FTC121K measures 0.108" diameter × 0.344" length (2.75mm × 8.75mm). CMF55121K00FHEB measures 0.090" diameter × 0.240" length (2.29mm × 6.10mm). Both are axial through-hole resistors compatible with standard PCB hole spacing, though the CMF55 series is more compact.

Q: Does packaging format affect electrical performance?

A: No. Tape & Reel and Cut Tape formats are packaging and delivery methods only. Electrical specifications remain identical. Packaging selection depends on assembly equipment and procurement volume requirements.

Q: Are both parts suitable for high-reliability applications?

A: Both parts are ROHS3 compliant and REACH unaffected. The CMF55121K00FHEB includes moisture-resistant construction, providing additional environmental protection. Consult specific application requirements and qualification standards for high-reliability determination.

Q: What is the significance of the ±50ppm/°C temperature coefficient?

A: This specification indicates resistance value stability across temperature variations. Both parts maintain this identical coefficient, ensuring equivalent performance in temperature-cycling environments. Over a 100°C temperature change, resistance variation remains within ±0.5% for both parts.