78F820J Equivalent & Substitute Parts

Part Overview

The Bourns 78F820J is an 82 µH unshielded drum core wirewound inductor rated for 132 mA with a maximum DC resistance of 3.2Ω. 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 78F820J is currently obsolete, making identification of compatible substitute parts essential for ongoing production and maintenance applications.

Substiute Parts

78F820J

Bourns Inc.In Stock: 66178F820J Datasheet

Current PartRFQ

78F820J-RC

Bourns Inc.In Stock: 707278F820J-RC Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The 78F820J-RC qualifies as a direct substitute based on the following critical parameters:

• Inductance Value: Both parts maintain 82 µH ±5% tolerance
• Core Type & Shielding: Identical ferrite drum core, unshielded construction
• Frequency Characteristics: Matching Q factor (60 @ 2.5 MHz) and self-resonant frequency (6 MHz)
• Mounting & Package: Both are through-hole axial components with identical physical dimensions (0.110" Dia × 0.280" L)
• Operating Temperature Range: Both rated -55°C to 105°C
• Series Designation: Both belong to the Bourns 78F series

The 78F820J-RC provides enhanced current handling capability (175 mA vs. 132 mA) and improved regulatory compliance, making it suitable for direct replacement in applications where the original part's current rating is adequate or where higher current capacity is beneficial.

Parameter Comparison

Engineering Selection Recommendations

The 78F820J-RC is the appropriate substitute for the obsolete 78F820J based on the following factors:

Product Status: The 78F820J is obsolete with no ongoing manufacturing. The 78F820J-RC maintains active production status, ensuring long-term availability and supply chain continuity.

Regulatory Compliance: The 78F820J-RC achieves ROHS3 compliance, whereas the original part is non-compliant. For applications subject to RoHS directives or customer requirements, the 78F820J-RC is the mandated choice.

Electrical Compatibility: The substitute part maintains identical inductance, tolerance, frequency characteristics, and operating temperature range. The increased current rating (175 mA vs. 132 mA) and slightly higher DC resistance (3.6Ω vs. 3.2Ω) are within acceptable substitution parameters for most circuit applications.

Physical Compatibility: Identical axial package dimensions and through-hole mounting ensure direct PCB compatibility without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can the 78F820J-RC replace the 78F820J in all applications?

A: Yes, for applications where the circuit current requirement does not exceed 132 mA. The 78F820J-RC's higher current rating (175 mA) provides additional margin. The 0.4Ω increase in DC resistance is negligible for most filter and coupling applications.

Q: What is the impact of the higher DC resistance in the 78F820J-RC?

A: The DC resistance increase from 3.2Ω to 3.6Ω represents a 12.5% change. In low-impedance circuits or high-current applications, this may introduce measurable voltage drop. Circuit simulation or bench testing is appropriate for critical applications.

Q: Are the physical dimensions identical between both parts?

A: Yes. Both parts measure 0.110" diameter × 0.280" length (2.79mm × 7.11mm) and use identical axial through-hole packaging, ensuring direct PCB compatibility.

Q: Why is RoHS compliance important for this substitution?

A: RoHS3 compliance ensures the part meets current environmental and hazardous substance restrictions. For new designs, products entering regulated markets, or customer specifications requiring RoHS compliance, the 78F820J-RC is the required choice.

Q: Are there any frequency-dependent differences between these parts?

A: No. Both parts maintain identical Q factor (60 @ 2.5 MHz) and self-resonant frequency (6 MHz), ensuring equivalent performance in frequency-dependent applications such as RF filtering or resonant circuits.