78F680J Equivalent & Substitute Parts

Part Overview

The Bourns 78F680J is a 68 µH unshielded drum core wirewound inductor rated for 137 mA with a maximum DC resistance of 2.9Ω. This through-hole axial component operates across the temperature range of -55°C to 105°C and is designed for applications requiring fixed inductance in compact form factors.

The 78F680J is classified as obsolete. Locating active production alternatives is necessary to ensure supply chain continuity and support for new designs or production restarts.

Substiute Parts

78F680J

Bourns Inc.In Stock: 92278F680J Datasheet

Current PartRFQ

78F680J-RC

Bourns Inc.In Stock: 972878F680J-RC Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The 78F680J-RC qualifies as a direct substitute based on the following alignment of critical parameters:

• Inductance Value: Both parts specify 68 µH with ±5% tolerance
• Core Type & Shielding: Identical ferrite drum core, unshielded construction
• Mounting & Package: Both are through-hole axial components with matching physical dimensions (0.110" Dia x 0.280" L)
• Frequency Characteristics: Identical Q factor (60 @ 2.5 MHz) and self-resonant frequency (6.5 MHz)
• Operating Temperature Range: Both rated -55°C to 105°C

The 78F680J-RC differs in current rating (185 mA vs. 137 mA) and DC resistance (3.3Ω vs. 2.9Ω). These differences represent an uprated variant within the same product family, making it suitable for applications where the original part's current capacity is insufficient or where slightly higher DC resistance is acceptable.

Parameter Comparison

Engineering Selection Recommendations

The 78F680J-RC is the active production equivalent for the obsolete 78F680J. Selection between these parts depends on application requirements and regulatory compliance:

Use 78F680J-RC when:

• New designs require active component availability
• RoHS3 compliance is mandatory
• Current requirements up to 185 mA are acceptable
• DC resistance up to 3.3Ω meets circuit specifications

Use 78F680J only when:

• Existing inventory supports legacy system maintenance
• Current rating must not exceed 137 mA
• DC resistance must remain at or below 2.9Ω
• RoHS non-compliance is acceptable for the application

Both parts maintain identical inductance, frequency response, and physical form factor, ensuring direct PCB compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the 78F680J-RC replace the 78F680J in existing designs?

A: Yes, provided the circuit tolerates the higher current rating (185 mA vs. 137 mA) and increased DC resistance (3.3Ω vs. 2.9Ω). The inductance value, frequency characteristics, and physical dimensions are identical, ensuring electrical and mechanical compatibility.

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

A: The 78F680J is RoHS non-compliant, while the 78F680J-RC is ROHS3 compliant. For applications subject to RoHS regulations or customer requirements, the 78F680J-RC is the only acceptable choice.

Q: Are there any PCB layout considerations when switching between these parts?

A: No. Both parts share identical axial package dimensions (0.110" Dia x 0.280" L) and through-hole mounting, requiring no PCB modifications.

Q: How do the DC resistance values affect circuit performance?

A: The 78F680J-RC has 0.4Ω higher DC resistance (3.3Ω vs. 2.9Ω). In low-impedance circuits or high-current applications, this difference may introduce measurable voltage drop. Verify that circuit design tolerances accommodate this variance.

Q: Is the 78F680J still available for purchase?

A: The 78F680J is classified as obsolete. The 78F680J-RC is the active production alternative with confirmed inventory availability.