78FR47K Equivalent & Substitute Parts

Part Overview

The Bourns 78FR47K is a 470 nH unshielded drum core wirewound inductor rated for 650 mA with a maximum DC resistance of 100 mOhm. This through-hole axial component operates across the temperature range of -55°C to 105°C and is designed for applications requiring low inductance values with high current capacity. The 78FR47K is classified as obsolete, making identification of suitable substitute components essential for ongoing design support and procurement.

Substiute Parts

78FR47K

Bourns Inc.In Stock: 68778FR47K Datasheet

Current PartRFQ

8230-12-RC

Bourns Inc.In Stock: 17398230-12-RC Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 78FR47K is determined by the following critical parameters:

• Inductance Value: Must match 470 nH ±10% tolerance
• Current Rating: Substitute must support minimum 650 mA operation
• DC Resistance: Lower DCR values are acceptable; higher values may impact circuit performance
• Mounting Configuration: Through-hole axial package required for mechanical compatibility
• Operating Temperature Range: Must support -55°C to 105°C minimum
• Shielding Classification: Unshielded specification must be maintained

The Bourns 8230-12-RC meets the inductance and mounting requirements. However, the substitute exhibits reduced current rating (590 mA versus 650 mA) and increased DC resistance (350 mOhm versus 100 mOhm), which represent functional trade-offs requiring circuit-level evaluation.

Parameter Comparison

Engineering Selection Recommendations

The 78FR47K is obsolete, necessitating alternative component selection for new procurement and ongoing support. The Bourns 8230-12-RC is an active product from the same manufacturer with matching inductance value and tolerance specification.

Compliance Considerations: The 8230-12-RC is ROHS3 compliant, whereas the 78FR47K is RoHS non-compliant. This distinction is significant for applications subject to regulatory compliance requirements.

Performance Trade-offs: The 8230-12-RC exhibits a 60 mA reduction in current rating (590 mA versus 650 mA) and a 250 mOhm increase in DC resistance (350 mOhm versus 100 mOhm). These differences result from different core materials: ferrite in the original part versus phenolic in the substitute. The quality factor (Q) is also reduced from 40 to 30 at 25 MHz.

Physical Compatibility: The 8230-12-RC has slightly larger dimensions (0.120" diameter and 0.300" length versus 0.110" diameter and 0.280" length). Verification of PCB layout and mechanical clearance is required prior to implementation.

Frequently Asked Questions (FAQ)

Q: Can the 8230-12-RC directly replace the 78FR47K in all applications?

A: Direct replacement requires circuit-level evaluation. The substitute meets the inductance specification but operates at reduced current capacity (590 mA versus 650 mA) and higher DC resistance (350 mOhm versus 100 mOhm). Applications operating near the 650 mA rating or sensitive to resistive losses require detailed analysis.

Q: What is the impact of increased DC resistance on circuit performance?

A: The 250 mOhm increase in DC resistance will generate additional heat dissipation and voltage drop across the inductor. In current-limiting or filtering applications, this may alter circuit behavior. Thermal and electrical simulations are recommended for critical designs.

Q: Are the physical dimension differences significant?

A: The 8230-12-RC is slightly larger in both diameter and length. PCB layout verification is necessary to confirm adequate clearance and mechanical fit within the existing design envelope.

Q: Why does the core material differ between these parts?

A: The 78FR47K uses ferrite core material, while the 8230-12-RC uses phenolic core material. This accounts for the differences in current rating, DC resistance, and quality factor. Both materials are suitable for unshielded through-hole axial inductors.

Q: Is RoHS compliance a factor in selecting the 8230-12-RC?

A: The 8230-12-RC is ROHS3 compliant, whereas the 78FR47K is not. For applications subject to RoHS regulations or customer requirements, the 8230-12-RC provides compliance alignment.

Q: What is the self-resonant frequency difference between these parts?

A: The 78FR47K has a self-resonant frequency of 330 MHz, while the 8230-12-RC is rated at 340 MHz. This 10 MHz difference is minimal and unlikely to impact most applications operating below these frequencies.