Bourns 78F102J Equivalent & Substitute Parts

Part Overview

The Bourns 78F102J is a 1 mH unshielded drum core wirewound inductor rated for 41 mA maximum current with 26Ohm DC resistance. 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 78F102J is classified as obsolete, making equivalent substitute parts necessary for ongoing production and maintenance applications. The 78F series provides direct mechanical and electrical compatibility within the specified parameter ranges.

Substiute Parts

78F102J

Bourns Inc.In Stock: 70478F102J Datasheet

Current PartRFQ

78F102J-RC

Bourns Inc.In Stock: 662378F102J-RC Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The 78F102J-RC qualifies as a direct substitute based on the following critical parameters:

Matching Parameters (Substitution Basis):

• Inductance: 1 mH (identical)
• Tolerance: ±5% (identical)
• Core Material: Ferrite (identical)
• Shielding: Unshielded (identical)
• Mounting Type: Through Hole (identical)
• Package: Axial (identical)
• Operating Temperature Range: -55°C to 105°C (identical)
• Q @ Frequency: 60 @ 790kHz (identical)
• Self Resonant Frequency: 1.2MHz (identical)
• Physical Dimensions: 0.110" Dia x 0.280" L (identical)
• Series: 78F (identical)

Allowable Parameter Variations:

• Current Rating: 78F102J-RC rated for 60 mA versus 78F102J at 41 mA (higher rating acceptable for drop-in replacement)
• DC Resistance: 78F102J-RC at 31.4Ohm Max versus 78F102J at 26Ohm Max (within acceptable tolerance for same inductance class)

Parameter Comparison

Engineering Selection Recommendations

The 78F102J-RC is the direct equivalent for the obsolete 78F102J. Selection is based on the following engineering criteria:

Product Status: The 78F102J is obsolete with no ongoing manufacturing. The 78F102J-RC maintains active production status, ensuring supply chain continuity and long-term availability.

Compliance: The 78F102J-RC achieves ROHS3 compliance, whereas the original 78F102J is non-compliant. For applications subject to RoHS regulations or environmental standards, the 78F102J-RC is the required choice.

Electrical Performance: Both parts maintain identical inductance (1 mH), tolerance (±5%), and frequency characteristics (Q @ 790kHz, 1.2MHz self-resonant frequency). The 78F102J-RC's higher current rating (60 mA vs. 41 mA) and slightly elevated DC resistance (31.4Ohm vs. 26Ohm) remain within acceptable operating parameters for circuits designed for the original part.

Mechanical Compatibility: Identical axial through-hole package, physical dimensions, and operating temperature range ensure direct board-level substitution without design modification.

Frequently Asked Questions (FAQ)

Q: Can the 78F102J-RC replace the 78F102J in existing designs?

A: Yes. The 78F102J-RC is a direct mechanical and electrical substitute. Identical inductance, tolerance, core material, shielding, package, and operating temperature range ensure compatibility. The higher current rating and slightly increased DC resistance do not compromise performance in circuits designed for the original 78F102J.

Q: What is the difference in DC resistance between these parts?

A: The 78F102J specifies 26Ohm maximum DC resistance, while the 78F102J-RC specifies 31.4Ohm maximum. This 5.4Ohm difference is within acceptable tolerance for the same inductance class and does not affect circuit functionality in standard applications.

Q: Why is the 78F102J-RC rated for higher current?

A: The 78F102J-RC is rated for 60 mA versus the 78F102J at 41 mA. This higher rating reflects manufacturing improvements in the active production version. The higher rating is compatible with designs requiring the original 41 mA specification.

Q: Are the physical dimensions identical?

A: Yes. Both parts measure 0.110" diameter by 0.280" length (2.79mm x 7.11mm). They are mechanically interchangeable in through-hole axial mounting applications.

Q: What is the RoHS compliance difference?

A: The 78F102J is RoHS non-compliant, while the 78F102J-RC is ROHS3 compliant. For applications requiring environmental or regulatory compliance, the 78F102J-RC is the appropriate selection.

Q: Do both parts have the same frequency characteristics?

A: Yes. Both parts maintain Q @ 60 at 790kHz and a self-resonant frequency of 1.2MHz. Frequency performance is identical.

Q: Is the 78F102J-RC available in different packaging options?

A: The 78F102J-RC is supplied in bulk packaging. The 78F102J was supplied in standard packaging. Both use identical axial through-hole package geometry.