LD1-3R9-R Equivalent & Substitute Parts

Part Overview

The LD1-3R9-R is a 3.9 µH unshielded drum core wirewound inductor manufactured by Eaton - Electronics Division. This surface mount component is rated for 1.75 A continuous current with a maximum DC resistance of 76 mOhm and operates across the temperature range of -40°C to 125°C. The part is currently active in production and RoHS compliant, making it suitable for modern electronic applications requiring fixed inductance in compact form factors.

Equivalent and substitute parts are identified when design requirements allow for alternative components that maintain functional compatibility within specified electrical and mechanical parameters. The SDR0403-3R9ML from Bourns Inc. serves as a direct substitute based on matching inductance value, DC resistance specification, operating temperature range, and physical package dimensions.

Substiute Parts

LD1-3R9-R

Eaton - Electronics DivisionIn Stock: 949LD1-3R9-R Datasheet

Current PartRFQ

SDR0403-3R9ML

Bourns Inc.In Stock: 10406SDR0403-3R9ML Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The SDR0403-3R9ML qualifies as a direct substitute for the LD1-3R9-R based on the following substitution criteria:

Matching Electrical Parameters:

• Inductance value: 3.9 µH (identical)
• Inductance tolerance: ±20% (identical)
• DC resistance: 76 mOhm Max (identical specification)
• Core material: Ferrite (identical)
• Shielding configuration: Unshielded (identical)
• Operating temperature range: -40°C to 125°C (identical)

Matching Mechanical Parameters:

• Mounting type: Surface Mount (identical)
• Package dimensions: 4.50mm L × 4.00mm W (identical footprint)
• Packaging format: Tape & Reel (TR) (identical)

Regulatory Compliance:

• RoHS compliance status: Both parts meet RoHS requirements
• ECCN classification: EAR99 (identical)
• HTSUS code: 8504.50.4000 (identical)

The SDR0403-3R9ML exhibits higher current rating (1.98 A vs. 1.75 A) and saturation current (2.7 A vs. 2.14 A), which provides additional design margin without introducing incompatibility. The maximum seated height differs by 0.10 mm (3.50 mm vs. 3.20 mm), which remains within typical PCB assembly tolerances for surface mount components.

Parameter Comparison

Engineering Selection Recommendations

Primary Selection (LD1-3R9-R): The LD1-3R9-R remains the specified component when design documentation explicitly requires Eaton Electronics Division sourcing or when inventory availability from the primary manufacturer is confirmed. This part is active in production with 932 pieces in stock and carries full RoHS compliance certification.

Substitute Selection (SDR0403-3R9ML): The SDR0403-3R9ML from Bourns Inc. is selected when:

• Primary part availability is constrained or lead times exceed project requirements
• Design specifications permit higher current ratings without adverse effects
• PCB layout accommodates the 0.30 mm additional height (3.50 mm vs. 3.20 mm maximum seated height)
• Sourcing from Bourns Inc. aligns with supply chain strategy

Both parts maintain identical electrical performance within the specified inductance, tolerance, DC resistance, and operating temperature parameters. The substitute part carries ROHS3 compliance, which exceeds the RoHS compliance requirement of the primary part. Inventory availability for the SDR0403-3R9ML is significantly higher (10,300 pieces in stock), supporting supply chain continuity.

Frequently Asked Questions (FAQ)

Q: Can the SDR0403-3R9ML be used as a direct replacement for the LD1-3R9-R without circuit redesign?

A: Yes, the SDR0403-3R9ML functions as a direct substitute within the specified electrical parameters. Both components provide 3.9 µH inductance with ±20% tolerance, 76 mOhm maximum DC resistance, and identical operating temperature range. The substitute part's higher current rating (1.98 A vs. 1.75 A) and saturation current (2.7 A vs. 2.14 A) provide additional design margin. PCB layout must accommodate the 0.30 mm height difference (3.50 mm vs. 3.20 mm maximum seated height).

Q: What are the critical parameters that must match for substitution?

A: Substitution requires matching of: inductance value (3.9 µH), inductance tolerance (±20%), DC resistance specification (76 mOhm Max), core material (Ferrite), shielding configuration (Unshielded), operating temperature range (-40°C to 125°C), and mounting type (Surface Mount). Physical footprint dimensions (4.50mm × 4.00mm) must also be compatible with PCB layout.

Q: Does the 0.30 mm height difference affect PCB assembly compatibility?

A: The SDR0403-3R9ML maximum seated height of 3.50 mm compared to the LD1-3R9-R maximum of 3.20 mm represents a 0.30 mm increase. This difference falls within standard PCB assembly tolerances for surface mount components. Verification is required only if the application involves height-constrained designs, such as components in close proximity to other tall parts or within confined enclosures.

Q: Are both parts RoHS compliant?

A: Yes. The LD1-3R9-R carries RoHS compliance certification. The SDR0403-3R9ML carries ROHS3 compliance certification, which represents an updated regulatory standard. Both parts meet RoHS requirements for lead-free manufacturing and restricted substance compliance.

Q: What is the difference in current rating between these parts?

A: The LD1-3R9-R is rated for 1.75 A continuous current with 2.14 A saturation current. The SDR0403-3R9ML is rated for 1.98 A continuous current with 2.7 A saturation current. The substitute part provides 0.23 A additional continuous current capacity and 0.56 A additional saturation margin, which reduces thermal stress and extends component life in current-limited applications.

Q: Can these parts be interchanged in existing inventory?

A: Interchangeability depends on design documentation and supply chain procedures. If the design specification permits equivalent parts meeting the stated electrical and mechanical parameters, the SDR0403-3R9ML can be substituted. If the design specification requires the LD1-3R9-R exclusively, substitution requires formal engineering change order approval. Both parts are packaged in Tape & Reel format and are compatible with standard surface mount assembly equipment.