LD1-1R8-R Equivalent & Substitute Parts

Part Overview

The LD1-1R8-R is a 1.8 µH unshielded drum core wirewound inductor manufactured by Eaton - Electronics Division. This surface mount component is rated for 2.35 A continuous current with a maximum DC resistance of 42 mOhm and operates across the temperature range of -40°C to 125°C. The part is RoHS Compliant and carries an active product status. Substitute parts are identified when equivalent electrical and mechanical specifications are required due to inventory constraints, supply chain considerations, or design flexibility within the allowed parameter tolerances.

Key Parameters

Parameter	Value	Significance for Substitution
Inductance	1.8 µH	Core electrical specification; must match exactly
Inductance Tolerance	±20%	Acceptable variation range for circuit operation
Current Rating (Continuous)	2.35 A	Minimum acceptable rating for thermal performance
DC Resistance (DCR)	42 mOhm Max	Power loss and thermal characteristics
Core Material	Ferrite	Electromagnetic performance and frequency response
Shielding	Unshielded	EMI characteristics and package footprint
Mounting Type	Surface Mount	PCB assembly compatibility
Package Dimensions	4.50mm L x 4.00mm W x 3.20mm H (Max)	PCB layout and spatial constraints
Operating Temperature Range	-40°C to 125°C	Environmental and thermal design requirements
RoHS Compliance	RoHS Compliant	Regulatory and environmental standards

Substitute Part Grouping Explanation

Substitution eligibility for the LD1-1R8-R is determined by strict adherence to the following electrical and mechanical parameters:

Mandatory Matching Parameters:

Inductance value: 1.8 µH (exact match required)
Inductance tolerance: ±20% (identical specification)
Core material: Ferrite (unshielded drum core wirewound type)
Mounting type: Surface Mount
Operating temperature range: -40°C to 125°C minimum
DC resistance: 42 mOhm maximum

Allowable Variation Parameters:

Current rating: Substitute must equal or exceed 2.35 A continuous rating
Current saturation (Isat): Substitute must equal or exceed 3.05 A
Package height: Substitute may vary within PCB assembly constraints (reference height 3.20mm maximum for LD1-1R8-R)
Packaging format: Tape & Reel (TR) or Cut Tape (CT) formats are both acceptable for manufacturing environments
RoHS compliance status: Both RoHS Compliant and ROHS3 Compliant are acceptable

The SDR0403-1R8ML meets all mandatory parameters and exceeds minimum current ratings, qualifying it as a direct electrical and mechanical substitute.

Parameter Comparison

Parameter	LD1-1R8-R (Eaton)	SDR0403-1R8ML (Bourns)	Compatibility Status
Inductance	1.8 µH	1.8 µH	Exact Match
Inductance Tolerance	±20%	±20%	Exact Match
Current Rating (Amps)	2.35 A	2.91 A	Substitute Exceeds Requirement
Current - Saturation (Isat)	3.05 A	4.4 A	Substitute Exceeds Requirement
DC Resistance (DCR)	42 mOhm Max	42 mOhm Max	Exact Match
Core Material	Ferrite	Ferrite	Exact Match
Shielding	Unshielded	Unshielded	Exact Match
Operating Temperature Range	-40°C to 125°C	-40°C to 125°C	Exact Match
Mounting Type	Surface Mount	Surface Mount	Exact Match
Size / Dimension	4.50mm L x 4.00mm W	4.50mm L x 4.00mm W	Exact Match
Height - Seated (Max)	3.20mm	3.50mm	Substitute Within Tolerance
RoHS Status	RoHS Compliant	ROHS3 Compliant	Both Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	Exact Match
Product Status	Active	Active	Both Active

Engineering Selection Recommendations

Primary Part: LD1-1R8-R (Eaton - Electronics Division)

The LD1-1R8-R remains the specified component when original design validation, existing inventory, or Eaton-specific supply chain requirements are in effect. This part carries active product status and full RoHS Compliance certification.

Substitute Part: SDR0403-1R8ML (Bourns Inc.)

The SDR0403-1R8ML qualifies as a direct substitute based on the following engineering criteria:

All mandatory electrical parameters match exactly: 1.8 µH inductance, ±20% tolerance, 42 mOhm maximum DC resistance, ferrite unshielded core
Current ratings exceed the primary part specification (2.91 A vs. 2.35 A continuous; 4.4 A vs. 3.05 A saturation), providing enhanced thermal margin
Mechanical compatibility is confirmed: identical footprint (4.50mm x 4.00mm), surface mount package, operating temperature range -40°C to 125°C
Regulatory compliance is maintained: ROHS3 Compliant status exceeds RoHS Compliant requirement
Both parts carry active product status with unlimited moisture sensitivity level (MSL 1)
Package height variation (3.50mm vs. 3.20mm maximum) remains within typical PCB assembly tolerances for nonstandard surface mount packages

The SDR0403-1R8ML is suitable for direct substitution in applications where Bourns supply chain availability is preferred or where the enhanced current rating provides design margin benefits.

Frequently Asked Questions (FAQ)

Q: Can the SDR0403-1R8ML be used as a direct replacement for the LD1-1R8-R in existing designs?

A: Yes. The SDR0403-1R8ML meets all mandatory electrical specifications (1.8 µH inductance, ±20% tolerance, 42 mOhm DCR) and mechanical requirements (4.50mm x 4.00mm footprint, surface mount, -40°C to 125°C operating range). The substitute part exceeds current ratings, providing additional thermal performance margin.

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

A: The LD1-1R8-R is rated for 2.35 A continuous current, while the SDR0403-1R8ML is rated for 2.91 A. The substitute part's higher rating indicates greater thermal capacity and lower power dissipation at equivalent current levels. Both parts maintain the same 42 mOhm maximum DC resistance, so the current rating difference reflects core design optimization rather than resistance variation.

Q: Are there packaging format differences between these parts?

A: Yes. The LD1-1R8-R is supplied in Tape & Reel (TR) format, while the SDR0403-1R8ML is supplied in Cut Tape (CT) & Digi-Reel® format. Both formats are standard for surface mount component manufacturing. Format selection depends on production equipment and assembly process requirements rather than electrical compatibility.

Q: Does the 0.30mm height difference affect PCB layout?

A: The LD1-1R8-R has a maximum seated height of 3.20mm, while the SDR0403-1R8ML is 3.50mm maximum. This 0.30mm difference is within typical PCB assembly tolerances for nonstandard surface mount packages and does not affect standard PCB layout or clearance calculations. Verify specific height constraints in your application if clearance is critical.

Q: Are both parts RoHS compliant?

A: Yes. The LD1-1R8-R carries RoHS Compliant certification, and the SDR0403-1R8ML carries ROHS3 Compliant certification. Both meet regulatory requirements for hazardous substance restrictions. ROHS3 represents an updated compliance standard and is fully acceptable as a substitute.

Q: What is the inductance tolerance, and does it affect circuit performance?

A: Both parts carry ±20% inductance tolerance. This means the actual inductance value may range from 1.44 µH to 2.16 µH. Circuit designs must account for this tolerance range in filter, impedance matching, or resonant frequency calculations. The tolerance is identical between the primary and substitute parts.

Q: Can these parts be used interchangeably in high-frequency applications?

A: Both parts are ferrite unshielded drum core wirewound inductors with identical core material and shielding characteristics. The SDR0403-1R8ML provides additional frequency response data (Q @ 7.96MHz = 28; Self Resonant Frequency = 90MHz), which may be relevant for high-frequency circuit analysis. Verify frequency-dependent performance requirements against the specific application operating frequency.

Q: What moisture sensitivity level applies to these parts?

A: Both the LD1-1R8-R and SDR0403-1R8ML carry Moisture Sensitivity Level (MSL) 1, which indicates unlimited shelf life and no moisture precautions required during storage or handling. Standard component storage conditions apply.

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