SC312MF-680 Equivalent & Substitute Parts

Part Overview

The SC312MF-680 is a 68 µH shielded wirewound inductor manufactured by Signal Transformer, rated for 210 mA continuous current with a maximum DC resistance of 4.1 Ohm. This component is classified as obsolete, making identification of suitable alternatives necessary for ongoing design support and production continuity. The part operates across the industrial temperature range of -40°C to 125°C and is ROHS3 compliant.

Substiute Parts

SC312MF-680

Signal TransformerIn Stock: 878SC312MF-680 Datasheet

Current PartRFQ

74404041680

Würth ElektronikIn Stock: 118974404041680 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SC312MF-680 is based on the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

• Inductance value: 68 µH ±20% tolerance
• Operating temperature range: -40°C to 125°C minimum
• Inductance test frequency: 100 kHz
• RoHS3 compliance requirement

Mechanical Compatibility Criteria:

• Surface mount technology
• Nonstandard package footprint (3.80mm x 3.80mm or compatible)
• Height constraint: 1.35 mm seated maximum or lower

Performance Considerations:

• Current rating must support the application's maximum continuous current requirement
• DC resistance and saturation current characteristics must be evaluated against circuit design specifications
• Shielding type (shielded or semi-shielded) may be interchangeable depending on EMI requirements

The substitute part 74404041680 (Würth Elektronik WE-LQS series) meets the core electrical requirements with identical inductance value and tolerance, matching operating temperature range, and ROHS3 compliance. The substitute offers improved DC resistance (1.495 Ohm vs. 4.1 Ohm) and higher current ratings (450 mA vs. 210 mA), making it suitable for applications requiring lower losses or higher current capacity.

Parameter Comparison

Engineering Selection Recommendations

The 74404041680 (Würth Elektronik WE-LQS series) is an active production substitute for the obsolete SC312MF-680. Both components maintain identical inductance specifications, tolerance, and operating temperature range, ensuring functional equivalence for the core inductor function.

Key selection factors:

Compliance & Availability: The substitute is in active production status with ROHS3 compliance and AEC-Q200 automotive qualification, providing long-term supply assurance and regulatory alignment.

Electrical Performance: The substitute exhibits superior electrical characteristics with lower DC resistance (1.495 Ohm vs. 4.1 Ohm) and higher current ratings (450 mA vs. 210 mA), reducing power dissipation and enabling operation in higher-current applications.

Mechanical Fit: The substitute footprint is slightly larger (4.00mm x 4.00mm vs. 3.80mm x 3.80mm) with reduced height (1.20 mm vs. 1.35 mm). PCB layout verification is required to confirm compatibility with existing design constraints.

Shielding Consideration: The substitute employs semi-shielded construction versus full shielding. EMI performance evaluation is necessary for noise-sensitive applications.

Frequently Asked Questions (FAQ)

Q: Can the 74404041680 directly replace the SC312MF-680 in existing designs?

A: Electrical substitution is valid based on matching inductance value, tolerance, and operating temperature range. Mechanical verification is required due to footprint differences (3.80mm vs. 4.00mm) and height variation (1.35mm vs. 1.20mm). PCB layout and shielding requirements must be assessed.

Q: What are the key differences between these two inductors?

A: The primary differences are DC resistance (4.1 Ohm vs. 1.495 Ohm), current rating (210 mA vs. 450 mA), shielding type (shielded vs. semi-shielded), and product status (obsolete vs. active). Inductance value and tolerance are identical.

Q: Is the semi-shielded construction of the substitute acceptable?

A: Semi-shielded construction provides reduced EMI performance compared to full shielding. Acceptance depends on the specific application's EMI requirements and circuit design. Electromagnetic compatibility testing may be necessary.

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

A: Lower DC resistance (1.495 Ohm vs. 4.1 Ohm) reduces power dissipation and heat generation, improving efficiency. This is beneficial for most applications and does not negatively impact circuit function.

Q: Are there any packaging or moisture sensitivity concerns?

A: Both components carry MSL Rating 1 (Unlimited), indicating no moisture sensitivity restrictions. The substitute is supplied in Tape & Reel packaging, standard for production environments.