78F561J Equivalent & Substitute Parts

Part Overview

The Bourns 78F561J is a 560 µH unshielded drum core wirewound inductor rated for 51 mA maximum current with 13 Ohm DC resistance. This through-hole axial component operates across -55°C to 105°C and is designed for applications requiring fixed inductance in the 560 µH range with ferrite core construction.

The 78F561J carries an obsolete product status. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements for legacy systems utilizing this component.

Substiute Parts

78F561J

Bourns Inc.In Stock: 88778F561J Datasheet

Current PartRFQ

78F561J-RC

Bourns Inc.In Stock: 78378F561J-RC Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 78F561J must maintain electrical and mechanical compatibility within the following criteria:

Critical Parameters for Substitution:

• Inductance value: 560 µH (exact match required)
• Inductance tolerance: ±5% (matching tolerance specification)
• Core material: Ferrite (unshielded drum core construction)
• Mounting type: Through hole axial configuration
• Physical dimensions: 0.110" Dia x 0.280" L (2.79mm x 7.11mm)
• Operating temperature range: -55°C ~ 105°C

Allowable Parameter Variations:

• Current rating: May exceed the original 51 mA specification
• DC resistance: May vary within acceptable limits for the inductance class
• Self-resonant frequency: Minor variations acceptable within ferrite drum core specifications
• Product status: Active status preferred for ongoing availability
• RoHS compliance: Upgrades to compliant versions acceptable

The 78F561J-RC substitute maintains identical inductance, tolerance, core material, shielding, mounting type, and physical dimensions while offering improved current handling (85 mA vs. 51 mA) and RoHS3 compliance.

Parameter Comparison

Engineering Selection Recommendations

The 78F561J-RC is the direct substitute for the obsolete 78F561J. Both components are manufactured by Bourns Inc. within the 78F series and share identical inductance specifications, core construction, and physical form factor.

The 78F561J-RC offers two primary advantages: active product status ensures continued availability and supply chain support, and ROHS3 compliance satisfies modern regulatory requirements for new designs and manufacturing processes. The increased current rating (85 mA vs. 51 mA) and slightly elevated DC resistance (15.5 Ohm vs. 13 Ohm) represent acceptable parameter variations for ferrite drum core inductors within this inductance class.

Selection of the 78F561J-RC is appropriate for applications where the original 78F561J is no longer available or where regulatory compliance is required. Electrical performance remains equivalent for circuits designed within the original 51 mA current specification.

Frequently Asked Questions (FAQ)

Q: Can the 78F561J-RC directly replace the 78F561J in existing designs?

A: Yes. Both components maintain identical inductance (560 µH), tolerance (±5%), core material (ferrite), shielding (unshielded), mounting type (through hole), and physical dimensions (0.110" Dia x 0.280" L). The 78F561J-RC is electrically and mechanically compatible with the original design.

Q: What is the significance of the higher current rating on the 78F561J-RC?

A: The 78F561J-RC supports 85 mA maximum current compared to 51 mA on the 78F561J. This represents improved current handling capability. Circuits designed for the original 51 mA specification operate safely within the substitute's rating.

Q: Does the increased DC resistance affect circuit performance?

A: The 78F561J-RC exhibits 15.5 Ohm maximum DC resistance versus 13 Ohm on the original. This 2.5 Ohm difference is within acceptable tolerance for ferrite drum core inductors in this class. Circuit designs should account for this variation in power dissipation calculations if operating near maximum current ratings.

Q: Why is RoHS3 compliance important for the substitute?

A: RoHS3 compliance ensures the component meets current environmental and regulatory standards for restricted hazardous substances. This is essential for new production runs, modern manufacturing processes, and markets with regulatory requirements.

Q: Are there any packaging differences between the two parts?

A: The 78F561J ships in standard packaging, while the 78F561J-RC is supplied in bulk packaging. Both maintain identical component specifications and through-hole axial form factor suitable for PCB assembly.

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

A: The 78F561J exhibits 2.3 MHz self-resonant frequency while the 78F561J-RC measures 2.35 MHz. This 0.05 MHz variation is negligible for most applications and falls within normal ferrite core manufacturing tolerances.