SCR105B-391 Equivalent & Substitute Parts

Part Overview

The SCR105B-391 is a 390 µH shielded surface mount inductor manufactured by Signal Transformer, rated for 700 mA continuous current with a maximum DC resistance of 1.34 Ohm. This component is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and production continuity. The part operates across an industrial temperature range of -40°C to 125°C and meets ROHS3 compliance requirements.

Substiute Parts

SCR105B-391

Signal TransformerIn Stock: 753SCR105B-391 Datasheet

Current PartRFQ

CDRH105RNP-391NC

Sumida America Components Inc.In Stock: 1166CDRH105RNP-391NC Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SCR105B-391 is determined by the following critical parameters:

• Inductance Value: 390 µH (tolerance range acceptable within ±20% to ±30%)
• Current Rating: Minimum 700 mA continuous current capability
• Saturation Current: Minimum 350 mA (substitute must meet or exceed this threshold)
• DC Resistance: Maximum 1.34 Ohm (lower values preferred for reduced power dissipation)
• Shielding: Shielded construction required
• Mounting Configuration: Surface mount, nonstandard package footprint
• Operating Temperature: Minimum -40°C to 100°C (substitute range of -40°C to 100°C is acceptable for most industrial applications)
• Compliance: ROHS3 compliance mandatory

The CDRH105RNP-391NC from Sumida America Components Inc. meets all substitution criteria with equivalent inductance, current rating, and shielding characteristics while maintaining compliance certifications.

Parameter Comparison

Engineering Selection Recommendations

The CDRH105RNP-391NC is a direct functional equivalent for the obsolete SCR105B-391. Selection is supported by the following factors:

• Product Availability: The substitute part is actively manufactured and maintained in production inventory (1071 pcs in stock), ensuring long-term supply continuity compared to the obsolete original part.
• Compliance Alignment: Both parts maintain ROHS3 compliance and identical moisture sensitivity ratings, eliminating regulatory or environmental qualification concerns.
• Electrical Performance: The substitute delivers superior DC resistance characteristics (953 mOhm vs. 1.34 Ohm), resulting in reduced power dissipation and improved thermal performance in the application circuit.
• Current Handling: Saturation current rating of 700 mA in the substitute exceeds the original specification of 350 mA, providing additional design margin for transient current conditions.
• Mechanical Compatibility: Surface mount configuration and nonstandard package footprint remain consistent, allowing direct PCB layout compatibility with minimal or no redesign.

Frequently Asked Questions (FAQ)

Q: Can the CDRH105RNP-391NC be used as a direct replacement for the SCR105B-391 without circuit modification?

A: Yes. Both parts share identical inductance values (390 µH), current ratings (700 mA), shielding characteristics, and surface mount configuration. The substitute exhibits lower DC resistance and higher saturation current, both of which are beneficial to circuit performance. Physical dimensions are within acceptable tolerance for nonstandard package footprints.

Q: What is the significance of the different inductance tolerances (±20% vs. ±30%)?

A: The original part specifies ±20% tolerance, while the substitute allows ±30%. In applications where inductance precision is critical, component selection from the substitute manufacturer's tighter tolerance bins may be required. For most filtering and impedance matching applications, the ±30% tolerance is functionally equivalent.

Q: Does the lower operating temperature maximum (100°C vs. 125°C) of the substitute affect compatibility?

A: The substitute's -40°C to 100°C range covers standard industrial operating conditions. Applications requiring sustained operation above 100°C ambient temperature should be evaluated against actual thermal modeling. For typical surface mount inductor applications with adequate PCB thermal management, the 100°C maximum is sufficient.

Q: How do the DC resistance differences impact circuit performance?

A: The substitute's 953 mOhm DCR is approximately 29% lower than the original 1.34 Ohm specification. This reduction decreases resistive losses and heat generation during operation, improving overall circuit efficiency. In current-limiting or series impedance applications, this difference should be verified against circuit design requirements.

Q: Are there packaging or tape & reel considerations for the substitute?

A: The substitute is supplied in Tape & Reel (TR) packaging, which is standard for automated assembly processes. The original part packaging specification is not detailed in the provided data. Verify tape pitch and reel compatibility with existing pick-and-place equipment before production implementation.