RNF12FTC681R Equivalent & Substitute Parts

Part Overview

The RNF12FTC681R is a 681 Ohm ±1% metal film through-hole resistor rated at 0.5W (1/2W) in axial package configuration, manufactured by Stackpole Electronics Inc. This component is designed for applications requiring precision resistance with flame retardant coating and safety features. The part maintains Active product status with 865 units currently in stock. Substitute parts are identified to provide alternative sourcing options when the primary part is unavailable or when design requirements permit equivalent component selection.

Substiute Parts

RNF12FTC681R

Stackpole Electronics IncIn Stock: 917RNF12FTC681R Datasheet

Current PartRFQ

CMF55681R00FHEB

Vishay DaleIn Stock: 5186CMF55681R00FHEB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the RNF12FTC681R is determined by the following critical parameters:

• Resistance value: 681 Ohms (exact match required)
• Tolerance: ±1% (exact match required)
• Power rating: 0.5W minimum (equal or higher acceptable)
• Composition: Metal Film (required for stability and temperature coefficient performance)
• Package: Axial Through-Hole (mechanical and electrical compatibility)
• Temperature coefficient: ±50ppm/°C or better (performance equivalence)
• Operating temperature range: Minimum -55°C to 155°C coverage (application dependent)
• Regulatory compliance: ROHS3 Compliant (mandatory for regulated applications)

The CMF55681R00FHEB from Vishay Dale meets all substitution criteria with identical electrical specifications and enhanced operating temperature range (-55°C to 175°C). Physical dimensions differ slightly but remain compatible with standard axial component footprints.

Parameter Comparison

Engineering Selection Recommendations

Both the RNF12FTC681R and CMF55681R00FHEB are Active status components with full ROHS3 compliance and REACH unaffected status, making them suitable for regulated applications. The CMF55681R00FHEB provides an extended operating temperature range to 175°C and includes moisture resistance features, offering enhanced environmental performance. Physical dimension differences (smaller diameter and length) may provide layout advantages in space-constrained designs. Selection between these parts should be based on availability, thermal environment requirements, and PCB layout constraints, as electrical performance is equivalent.

Frequently Asked Questions (FAQ)

Q: Can the CMF55681R00FHEB replace the RNF12FTC681R in all applications?

A: Yes, provided the smaller physical dimensions (0.090" diameter × 0.240" length versus 0.108" × 0.344") are compatible with your PCB layout and mechanical assembly. Electrical specifications are identical.

Q: What is the significance of the ±1% tolerance specification?

A: The ±1% tolerance ensures the actual resistance value remains within 674.19 Ohms to 687.81 Ohms, critical for precision circuit applications. Substitute parts must maintain this tolerance specification.

Q: Does the extended temperature range of the CMF55681R00FHEB affect compatibility?

A: No. The extended range (-55°C to 175°C versus -55°C to 155°C) provides additional operational margin and does not create incompatibility. Applications requiring only -55°C to 155°C operation remain fully compatible.

Q: Are there packaging differences between these parts?

A: The RNF12FTC681R is supplied in Tape & Reel (TR) packaging, while the CMF55681R00FHEB is available in Cut Tape (CT) packaging. Both are suitable for automated assembly; packaging selection depends on production volume and handling requirements.

Q: What does the metal film composition guarantee?

A: Metal film construction provides stable resistance values across temperature variations (±50ppm/°C coefficient), superior frequency response, and low noise characteristics compared to carbon film alternatives.