ELJ-FD4R7KF Equivalent & Substitute Parts

Part Overview

The ELJ-FD4R7KF is a 4.7 µH unshielded wirewound inductor manufactured by Panasonic Electronic Components, rated for 130 mA maximum current with a DC resistance of 3.38Ohm Max. This component is packaged in the 0805 (2012 Metric) surface mount form factor. The product is currently obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and production continuity.

Substiute Parts

ELJ-FD4R7KF

Panasonic Electronic ComponentsIn Stock: 820ELJ-FD4R7KF Datasheet

Current PartRFQ

744760347A

Würth ElektronikIn Stock: 16280744760347A Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the ELJ-FD4R7KF is determined by the following critical parameters:

• Inductance Value: Must be 4.7 µH
• Current Rating: Substitute must support minimum 130 mA; higher ratings are acceptable
• DC Resistance (DCR): Lower or equal DCR values are preferred to maintain circuit performance
• Shielding Configuration: Unshielded topology must be maintained
• Q Factor @ 7.96MHz: Comparable performance at test frequency
• Self Resonant Frequency: Must support operational bandwidth
• Surface Mount Package: 0805 (2012 Metric) form factor or compatible nonstandard equivalent
• Physical Dimensions: Must fit within or match PCB layout constraints

The Würth Elektronik 744760347A meets these substitution criteria with equivalent inductance, superior current rating (180 mA vs. 130 mA), lower DC resistance (2.8Ohm Max vs. 3.38Ohm Max), and active product status.

Parameter Comparison

Engineering Selection Recommendations

The 744760347A from Würth Elektronik is a direct functional substitute for the obsolete ELJ-FD4R7KF. Selection is based on the following factors:

Product Status: The ELJ-FD4R7KF is obsolete, while the 744760347A is active and in production, ensuring long-term availability and supply chain continuity.

Electrical Performance: Both inductors maintain identical inductance values (4.7 µH) and Q factors (15 @ 7.96MHz). The 744760347A provides superior performance with lower DC resistance (2.8Ohm Max vs. 3.38Ohm Max) and higher current rating (180 mA vs. 130 mA), reducing power dissipation and thermal stress in the circuit.

Compliance: The 744760347A is ROHS3 compliant and REACH unaffected, meeting modern regulatory requirements. The ELJ-FD4R7KF is RoHS non-compliant, which may restrict use in new designs or regulated applications.

Physical Compatibility: The 744760347A uses a nonstandard package with dimensions of 0.090" L x 0.067" W (2.29mm x 1.70mm), compared to the standard 0805 (2012 Metric) form factor of the original part. PCB layout verification is required to confirm fit within existing footprints, as the substitute is slightly larger in length and width while maintaining comparable height.

Frequently Asked Questions (FAQ)

Q: Can the 744760347A be used as a direct replacement for the ELJ-FD4R7KF?

A: Yes, the 744760347A is functionally equivalent for applications requiring 4.7 µH inductance at 130 mA or lower current levels. Both components share identical inductance values, tolerance specifications at test frequency, and unshielded topology. Physical footprint verification is necessary due to the nonstandard package dimensions of the substitute.

Q: What are the key differences between these two inductors?

A: The primary differences are product status (obsolete vs. active), DC resistance (3.38Ohm Max vs. 2.8Ohm Max), current rating (130 mA vs. 180 mA), tolerance (±10% vs. ±5%), self-resonant frequency (30MHz vs. 50MHz), and regulatory compliance (RoHS non-compliant vs. ROHS3 compliant). The 744760347A offers superior electrical performance and modern compliance certifications.

Q: Will the larger physical dimensions of the 744760347A affect PCB layout?

A: The 744760347A is 0.011" longer and 0.018" wider than the ELJ-FD4R7KF, with comparable height. PCB footprint and clearance requirements must be evaluated for each application. Height-constrained designs may require layout adjustment.

Q: Are there any impedance or frequency response differences?

A: Both inductors are tested at 7.96 MHz with identical Q factors of 15. The 744760347A has a higher self-resonant frequency (50MHz vs. 30MHz), providing extended usable bandwidth. DC resistance is lower in the substitute, resulting in reduced insertion loss.

Q: What is the impact of lower DC resistance on circuit performance?

A: Lower DC resistance (2.8Ohm Max vs. 3.38Ohm Max) reduces power dissipation and heat generation, improving efficiency and thermal stability. This is beneficial for current-limited applications and extends component lifespan.

Q: Is the ±5% tolerance of the 744760347A compatible with designs specified for ±10%?

A: Yes. The tighter ±5% tolerance of the 744760347A is a performance improvement over the ±10% specification of the original part and will not cause compatibility issues in circuits designed for ±10% tolerance.