SC105B-120 Equivalent & Substitute Parts

Part Overview

The SC105B-120 is a 12 µH unshielded wirewound inductor manufactured by Signal Transformer, rated for 3.2 A continuous current with a maximum DC resistance of 70mOhm. This component is classified as obsolete, making substitute parts necessary for new designs and ongoing production requirements. The part operates across an industrial temperature range of -40°C to 125°C and meets ROHS3 compliance standards.

Substiute Parts

SC105B-120

Signal TransformerIn Stock: 1028SC105B-120 Datasheet

Current PartRFQ

#B966AS-120M=P3

Murata ElectronicsIn Stock: 1439#B966AS-120M=P3 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SC105B-120 is determined by the following critical parameters:

• Inductance Value: 12 µH (±20% tolerance maintained)
• Current Rating: Minimum 3.2 A continuous current capability
• DC Resistance: Lower or equal to 70 mOhm preferred for thermal performance
• Mounting Type: Surface Mount configuration required
• Operating Temperature: Must support -40°C minimum; 125°C operation preferred but -40°C to 85°C acceptable with thermal margin verification
• Compliance: ROHS3 and REACH compliance required

The Murata Electronics #B966AS-120M=P3 qualifies as a direct substitute based on matching inductance, exceeding current rating requirements, and maintaining compliance certifications. Shielding differences and core material variations are acceptable within the allowed parameter set for this application category.

Parameter Comparison

Engineering Selection Recommendations

The #B966AS-120M=P3 from Murata Electronics is the qualified substitute for the obsolete SC105B-120. Selection is based on the following engineering criteria:

Electrical Compatibility: Both parts maintain 12 µH inductance with ±20% tolerance. The substitute provides superior current handling (3.7 A vs. 3.2 A) and lower DC resistance (35 mOhm vs. 70 mOhm), resulting in reduced thermal dissipation and improved efficiency.

Compliance and Availability: The substitute is active in production with 1354 units in stock, compared to the obsolete main part with 949 units. Both parts maintain ROHS3 compliance, REACH unaffected status, and MSL 1 rating.

Temperature Consideration: The substitute operates to 85°C maximum versus 125°C for the main part. Applications requiring sustained operation above 85°C require thermal analysis to confirm the substitute's adequacy within the circuit design.

Physical and Mechanical: Both parts are surface mount with nonstandard package dimensions. The substitute is slightly larger (10.40mm x 10.40mm vs. 10.90mm x 9.80mm) and taller (6.80mm vs. 6.00mm). PCB layout verification is required.

Frequently Asked Questions (FAQ)

Q: Can the #B966AS-120M=P3 directly replace the SC105B-120 in all applications?

A: The substitute meets all critical electrical parameters (inductance, current rating, DC resistance) and compliance requirements. However, applications operating continuously above 85°C require thermal margin verification. Physical dimensions differ slightly; PCB layout confirmation is necessary.

Q: What is the impact of the shielding difference?

A: The SC105B-120 is unshielded while the #B966AS-120M=P3 is shielded. Shielding reduces electromagnetic interference emission and susceptibility. For applications sensitive to EMI, the shielded substitute may provide improved performance. For applications where unshielded operation is critical, shielding effects must be evaluated in the circuit context.

Q: Why is the DC resistance lower on the substitute?

A: The #B966AS-120M=P3 uses a drum core ferrite construction versus the wirewound design of the SC105B-120. Lower DC resistance (35 mOhm vs. 70 mOhm) reduces I²R losses and heat generation, improving thermal performance and efficiency.

Q: Are there packaging or supply chain considerations?

A: The substitute is supplied in Cut Tape (CT) packaging and is currently in active production with higher inventory availability. The main part is obsolete with limited remaining stock. For new designs and long-term production, the substitute ensures supply continuity.

Q: What parameters must match for substitution to be valid?

A: Inductance value (12 µH ±20%), current rating (minimum 3.2 A), surface mount configuration, and compliance certifications (ROHS3, REACH) are mandatory matching criteria. DC resistance, shielding, and core material may vary within the allowed parameter set for this inductor category.