Equivalent & Substitute Parts for Würth Elektronik 744773039

Part Overview

The Würth Elektronik 744773039 is a 3.9 µH unshielded drum core wirewound inductor rated for 1.88 A continuous current with a maximum DC resistance of 94 mOhm. This surface mount component operates across the industrial temperature range of -40°C to 125°C and is classified as Active product status. Substitute parts are identified to provide design flexibility when the primary part is unavailable or when alternative electrical characteristics better suit specific application requirements.

Key Parameters

Parameter	Value
Inductance	3.9 µH
Inductance Tolerance	±20%
Current Rating	1.88 A
Current - Saturation (Isat)	2.57 A
DC Resistance (DCR)	94 mOhm Max
Core Material	Ferrite
Shielding	Unshielded
Mounting Type	Surface Mount
Package Type	Nonstandard
Physical Dimensions	4.50mm L x 4.00mm W x 4.60mm H
Operating Temperature Range	-40°C to 125°C
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	MSL 1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the 744773039 are qualified based on the following critical parameters:

Inductance value within tolerance band (3.9 µH ±20%)
Current rating sufficient for application requirements (minimum 1.88 A)
DC resistance compatible with thermal and efficiency constraints
Surface mount nonstandard package with equivalent footprint dimensions
Operating temperature range matching or exceeding -40°C to 125°C
Ferrite core construction for unshielded drum core wirewound topology
RoHS3 compliance and MSL 1 rating for manufacturing compatibility

The identified substitutes maintain electrical equivalence within these parameters while offering alternative sourcing options.

Parameter Comparison

Parameter	Würth Elektronik 744773039	Bourns SDR0403-3R9ML	Pulse Electronics PF0580.382NL
Inductance	3.9 µH	3.9 µH	3.8 µH
Inductance Tolerance	±20%	±20%	±15%
Current Rating (Amps)	1.88 A	1.98 A	1.7 A
Current - Saturation (Isat)	2.57 A	2.7 A	1.7 A
DC Resistance (DCR)	94 mOhm Max	76 mOhm Max	68 mOhm Max
Shielding	Unshielded	Unshielded	Unshielded
Operating Temperature	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Physical Dimensions (L x W x H)	4.50mm x 4.00mm x 4.60mm	4.50mm x 4.00mm x 4.60mm	4.70mm x 4.20mm x 3.48mm
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	MSL 1	MSL 1	MSL 1

Engineering Selection Recommendations

All three components maintain Active product status and ROHS3 compliance with MSL 1 rating, ensuring manufacturing compatibility and regulatory alignment.

The Bourns SDR0403-3R9ML provides direct electrical equivalence with identical inductance and tolerance specifications. The component offers improved current saturation performance (2.7 A versus 2.57 A) and reduced DC resistance (76 mOhm versus 94 mOhm), resulting in lower thermal dissipation. Physical footprint dimensions are identical, enabling direct board-level substitution.

The Pulse Electronics PF0580.382NL operates within the inductance tolerance band with a tighter tolerance specification (±15%). The current rating of 1.7 A falls below the primary part specification and requires application-level evaluation. The DC resistance of 68 mOhm is the lowest among the three options. Physical dimensions show minor variation (4.70mm x 4.20mm versus 4.50mm x 4.00mm), requiring PCB layout verification for footprint compatibility.

Frequently Asked Questions (FAQ)

Q: Can the Bourns SDR0403-3R9ML directly replace the Würth Elektronik 744773039?

A: Yes. Both components share identical inductance (3.9 µH), tolerance (±20%), operating temperature range (-40°C to 125°C), and physical dimensions (4.50mm x 4.00mm x 4.60mm). The Bourns part offers superior electrical performance with higher saturation current and lower DC resistance.

Q: Is the Pulse Electronics PF0580.382NL suitable as a substitute?

A: The PF0580.382NL operates within the inductance tolerance band (3.8 µH falls within 3.9 µH ±20%). However, the current rating of 1.7 A is below the primary part specification of 1.88 A. Application requirements must be evaluated to determine if this reduced current rating is acceptable. Physical dimensions differ slightly and require PCB layout verification.

Q: What are the key differences in DC resistance among these parts?

A: The Würth Elektronik 744773039 specifies 94 mOhm maximum, the Bourns SDR0403-3R9ML specifies 76 mOhm maximum, and the Pulse Electronics PF0580.382NL specifies 68 mOhm maximum. Lower DC resistance reduces power dissipation and thermal generation in the inductor.

Q: Are all three parts compatible with the same PCB footprint?

A: The Würth Elektronik 744773039 and Bourns SDR0403-3R9ML share identical dimensions and are footprint-compatible. The Pulse Electronics PF0580.382NL has slightly larger dimensions (4.70mm x 4.20mm) and requires PCB layout verification before substitution.

Q: Do all parts meet the same compliance requirements?

A: Yes. All three components are ROHS3 compliant with MSL 1 rating, ensuring compatibility with standard manufacturing processes and regulatory requirements.

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