RNF12FTC40K2 Equivalent & Substitute Parts

Part Overview

The RNF12FTC40K2 is a 40.2 kOhms ±1% metal film axial through-hole resistor rated at 0.5W (1/2W) manufactured by Stackpole Electronics Inc. This component features flame retardant coating and safety-grade construction, designed for applications requiring precision resistance values with high reliability. The part is currently in active production status with 1019 units in stock. Substitute parts are identified when equivalent electrical specifications, mechanical compatibility, and regulatory compliance can be maintained across alternative manufacturers.

Substiute Parts

RNF12FTC40K2

Stackpole Electronics IncIn Stock: 1037RNF12FTC40K2 Datasheet

Current PartRFQ

CMF5540K200FHEB

Vishay DaleIn Stock: 1654CMF5540K200FHEB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the RNF12FTC40K2 is determined by the following critical parameters:

• Resistance value: 40.2 kOhms (exact match required)
• Tolerance: ±1% (equivalent or tighter tolerance acceptable)
• Power rating: 0.5W minimum (equal or higher acceptable)
• Composition: Metal film (maintains electrical performance characteristics)
• Package: Axial through-hole (mechanical compatibility with PCB layout)
• Temperature coefficient: ±50ppm/°C or better (stability requirement)
• Operating temperature range: Minimum -55°C ~ 155°C (application environment compatibility)
• Regulatory compliance: ROHS3 Compliant, REACH Unaffected (mandatory for equivalent parts)

The CMF5540K200FHEB from Vishay Dale meets all substitution criteria with identical electrical specifications and enhanced operating temperature range (-55°C ~ 175°C).

Parameter Comparison

Engineering Selection Recommendations

The CMF5540K200FHEB is a direct electrical equivalent to the RNF12FTC40K2. Both components maintain identical resistance, tolerance, power rating, and temperature coefficient specifications. The substitute part offers an extended operating temperature range (175°C maximum versus 155°C) and includes moisture-resistant properties in addition to flame retardant coating.

Both parts are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements. The CMF5540K200FHEB features a smaller physical footprint (0.090" diameter x 0.240" length compared to 0.108" x 0.344"), which may provide layout advantages in space-constrained applications while maintaining full electrical compatibility.

Selection between these parts should be based on packaging availability (Tape & Reel for RNF12FTC40K2 versus Cut Tape for CMF5540K200FHEB), physical space constraints, and supply chain considerations.

Frequently Asked Questions (FAQ)

Q: Can the CMF5540K200FHEB replace the RNF12FTC40K2 in existing designs?

A: Yes. Both components share identical electrical specifications: 40.2 kOhms ±1% resistance, 0.5W power rating, ±50ppm/°C temperature coefficient, and metal film composition. Both are axial through-hole packages suitable for PCB mounting. The substitute part has a smaller physical size and extended temperature range, making it functionally compatible.

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

A: The RNF12FTC40K2 measures 0.108" diameter x 0.344" length (2.75mm x 8.75mm). The CMF5540K200FHEB measures 0.090" diameter x 0.240" length (2.29mm x 6.10mm). The substitute is more compact, which may affect PCB layout spacing and lead bend radius considerations.

Q: Are both parts compliant with current environmental regulations?

A: Yes. Both the RNF12FTC40K2 and CMF5540K200FHEB are ROHS3 compliant and REACH unaffected, meeting current environmental and hazardous substance restrictions.

Q: What is the difference in packaging format?

A: The RNF12FTC40K2 is supplied in Tape & Reel (TR) format, while the CMF5540K200FHEB is supplied in Cut Tape (CT) format. This affects handling, storage, and automated assembly processes but does not impact electrical performance.

Q: Does the CMF5540K200FHEB offer any performance advantages?

A: The CMF5540K200FHEB extends the maximum operating temperature to 175°C (compared to 155°C for the RNF12FTC40K2) and includes moisture-resistant properties. These features provide enhanced reliability in high-temperature and humid environments while maintaining identical electrical performance at standard operating conditions.