SC312MF-3R3 Equivalent & Substitute Parts

Part Overview

The SC312MF-3R3 is a 3.3 µH shielded wirewound inductor manufactured by Signal Transformer, rated for 980 mA continuous current with a maximum DC resistance of 210mOhm. This component is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements. The part operates across the temperature range of -40°C to 125°C and is ROHS3 compliant with unlimited moisture sensitivity rating.

Substiute Parts

SC312MF-3R3

Signal TransformerIn Stock: 940SC312MF-3R3 Datasheet

Current PartRFQ

1229AS-H-3R3M=P3

Murata ElectronicsIn Stock: 26321229AS-H-3R3M=P3 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SC312MF-3R3 is determined by the following critical parameters:

• Inductance Value: Must be 3.3 µH with ±20% tolerance
• Shielding: Must be shielded to maintain electromagnetic isolation
• Current Rating: Must support minimum 980 mA continuous operation
• DC Resistance: Lower or equivalent DCR is acceptable; higher values may impact circuit performance
• Saturation Current: Must meet or exceed 1.8 A minimum saturation threshold
• Mounting Type: Surface mount configuration required
• Operating Temperature: Must support -40°C to 125°C range or equivalent
• RoHS Compliance: ROHS3 compliance required for regulatory alignment
• Physical Dimensions: Footprint compatibility within nonstandard package constraints

The substitute part 1229AS-H-3R3M=P3 meets these criteria with enhanced electrical performance characteristics.

Parameter Comparison

Engineering Selection Recommendations

The 1229AS-H-3R3M=P3 from Murata Electronics is the qualified substitute for the obsolete SC312MF-3R3. Selection is based on the following factors:

Product Status: The SC312MF-3R3 is obsolete, requiring transition to an active component. The 1229AS-H-3R3M=P3 maintains active production status with established supply chain availability.

Electrical Compatibility: Both components share identical inductance values (3.3 µH) and tolerance specifications (±20%). The substitute provides superior DC resistance performance (95 mOhm vs. 210 mOhm), reducing resistive losses in the circuit. The substitute's higher current rating (1.65 A vs. 980 mA) provides additional design margin.

Regulatory Compliance: Both parts are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Physical Compatibility: Dimensional differences are minimal. The substitute is slightly smaller in footprint (3.70mm x 3.90mm vs. 3.80mm x 3.80mm) and lower in height (1.20mm vs. 1.35mm), offering improved PCB layout flexibility.

Temperature Operating Range: The substitute operates to 85°C maximum, compared to the main part's 125°C. Applications requiring operation above 85°C require thermal analysis or alternative component selection.

Frequently Asked Questions (FAQ)

Q: Can the 1229AS-H-3R3M=P3 directly replace the SC312MF-3R3 in existing designs?

A: Yes, for applications operating within -40°C to 85°C. The substitute meets or exceeds all critical electrical parameters: identical inductance and tolerance, higher current rating, and lower DC resistance. Physical dimensions are compatible with nonstandard package footprints. Applications requiring operation above 85°C require thermal evaluation.

Q: What is the impact of the lower saturation current in the substitute (1.3 A vs. 1.8 A)?

A: The substitute's saturation current of 1.3 A is lower than the main part's 1.8 A. For applications where the circuit current approaches or exceeds 1.3 A, saturation characteristics must be evaluated. The substitute's higher continuous current rating (1.65 A) provides operational margin for most standard applications.

Q: Are there packaging differences between these components?

A: The main part uses nonstandard packaging with Tape & Reel availability for the substitute. Both are surface mount components with compatible footprints. The substitute's reduced height (1.20mm vs. 1.35mm) may improve PCB assembly clearance.

Q: What are the compliance certifications for both parts?

A: Both the SC312MF-3R3 and 1229AS-H-3R3M=P3 are ROHS3 compliant and REACH unaffected. Both carry MSL rating of 1 (unlimited moisture sensitivity), requiring standard handling procedures.

Q: How does the lower DC resistance of the substitute affect circuit performance?

A: The substitute's DC resistance of 95 mOhm (versus 210 mOhm) reduces resistive losses by approximately 55%. This results in lower heat generation and improved efficiency in current-carrying applications, providing a performance advantage over the original component.