Bourns 78F3R3J Equivalent & Substitute Parts

Part Overview

The Bourns 78F3R3J is a 3.3 µH unshielded drum core wirewound inductor rated for 270 mA with a maximum DC resistance of 340mOhm. This through-hole axial component operates across -55°C to 105°C and is designed for applications requiring fixed inductance in compact form factors. The 78F series is currently obsolete, making equivalent substitutes necessary for ongoing production and maintenance applications.

Substiute Parts

78F3R3J

Bourns Inc.In Stock: 107378F3R3J Datasheet

Current PartRFQ

8230-32-RC

Bourns Inc.In Stock: 31508230-32-RC Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 78F3R3J is based on maintaining electrical and mechanical compatibility within the following criteria:

• Inductance Value: Must be 3.3 µH (primary electrical requirement)
• Core Type & Shielding: Ferrite drum core, unshielded construction
• Mounting & Package: Through-hole axial configuration
• Operating Temperature Range: -55°C to 105°C minimum
• Test Frequency: 7.9 MHz measurement standard

The Bourns 8230-32-RC meets these core substitution criteria. While it exhibits higher DC resistance (850mOhm vs. 340mOhm) and lower current rating (380 mA vs. 270 mA), these parameters remain within acceptable tolerance for applications where the 78F3R3J was specified, provided circuit design accommodates the increased resistance characteristics.

Parameter Comparison

Engineering Selection Recommendations

The 8230-32-RC serves as the primary substitute for the obsolete 78F3R3J based on matching inductance value, core type, and through-hole axial package configuration. The substitute part is currently in active production status with improved regulatory compliance (ROHS3).

Circuit designers must account for the increased DC resistance of the 8230-32-RC (850mOhm vs. 340mOhm), which will result in higher power dissipation and voltage drop across the inductor. Applications operating at or near the 270 mA current limit of the original part should evaluate whether the 380 mA rating of the substitute provides adequate margin, and whether the higher resistance introduces unacceptable losses in the target circuit.

The ±10% inductance tolerance of the substitute part is wider than the ±5% tolerance of the original; circuits with tight inductance specifications should account for this variance.

Frequently Asked Questions (FAQ)

Q: Can the 8230-32-RC be used as a direct drop-in replacement for the 78F3R3J?

A: Physical and electrical compatibility exists for through-hole axial mounting. However, the increased DC resistance (850mOhm vs. 340mOhm) will affect circuit performance. Verification of acceptable power dissipation and voltage drop is required before implementation.

Q: What is the impact of the higher DC resistance in the substitute part?

A: Higher DC resistance increases resistive losses proportional to I²R. At 270 mA, the 78F3R3J dissipates approximately 24.8 mW, while the 8230-32-RC dissipates approximately 61.9 mW at the same current. Circuit thermal design and performance specifications must accommodate this difference.

Q: Does the wider inductance tolerance of the 8230-32-RC affect substitution?

A: The ±10% tolerance of the substitute is wider than the ±5% tolerance of the original part. Applications with inductance-critical specifications (such as resonant frequency tuning) should evaluate whether this tolerance range remains acceptable for the target circuit function.

Q: Are there packaging or dimensional differences between these parts?

A: Both parts use through-hole axial packages. The 8230-32-RC has slightly larger dimensions (0.120" Dia x 0.300" L vs. 0.110" Dia x 0.280" L). PCB layout verification is recommended to confirm clearance compatibility.

Q: What is the significance of the RoHS compliance difference?

A: The 78F3R3J is RoHS non-compliant, while the 8230-32-RC is ROHS3 compliant. For applications subject to RoHS regulations or customer requirements, the substitute part provides regulatory alignment.