SPD74-393M Equivalent & Substitute Parts

Part Overview

The SPD74-393M is a 39 µH shielded drum core wirewound inductor manufactured by API Delevan Inc., rated for 1.4 A with a maximum DC resistance of 230 mOhm. This surface mount component operates across -55°C to 125°C and features ferrite core construction with ±20% inductance tolerance. The part is currently obsolete, making equivalent substitutes necessary for ongoing production and maintenance applications requiring compatible 39 µH inductors in nonstandard surface mount packages.

Key Parameters

Parameter	SPD74-393M
Inductance	39 µH
Inductance Tolerance	±20%
Current Rating	1.4 A
DC Resistance (Max)	230 mOhm
Shielding	Shielded
Core Material	Ferrite
Operating Temperature Range	-55°C to 125°C
Mounting Type	Surface Mount
Package Type	Nonstandard
Size	7.30mm x 7.30mm x 4.70mm (max height)

Substitute Part Grouping Explanation

Substitution eligibility for the SPD74-393M is determined by the following critical parameters:

Inductance Value: All substitutes must maintain 39 µH ±20% tolerance
Shielding: All substitutes must be shielded to maintain electromagnetic isolation
Mounting Type: All substitutes must be surface mount compatible
Core Material: Ferrite core construction preferred for consistency
Current Rating: Substitutes must support minimum 1.4 A or higher
DC Resistance: Substitutes with 230 mOhm or lower are acceptable
Operating Temperature: Substitutes must cover the -55°C to 125°C range or equivalent
Package Compatibility: Nonstandard surface mount packages with similar footprint dimensions (7.30mm x 7.30mm nominal)

Four substitute parts meet these criteria: HRSPD74-393M, SCRH74-390, SCRH74B-390, and SRR0745A-390M.

Parameter Comparison

Parameter	SPD74-393M	HRSPD74-393M	SCRH74-390	SCRH74B-390	SRR0745A-390M
Manufacturer	API Delevan Inc.	API Delevan Inc.	Signal Transformer	Signal Transformer	Bourns Inc.
Inductance	39 µH	39 µH	39 µH	39 µH	39 µH
Tolerance	±20%	±20%	±20%	±20%	±20%
Current Rating	1.4 A	850 mA	910 mA	910 mA	1.17 A
DC Resistance (Max)	230 mOhm	200 mOhm	230 mOhm	230 mOhm	190 mOhm
Shielding	Shielded	Shielded	Shielded	Shielded	Shielded
Operating Temperature	-55°C to 125°C	-55°C to 130°C	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	Non-compliant	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Size (L x W)	7.30mm x 7.30mm	7.37mm x 7.37mm	7.80mm x 7.80mm	7.80mm x 7.80mm	7.30mm x 7.30mm
Height (Max)	4.70mm	5.03mm	4.50mm	4.50mm	4.70mm

Engineering Selection Recommendations

HRSPD74-393M (API Delevan Inc.): Direct manufacturer equivalent with identical inductance and DC resistance specifications. Maintains ferrite core construction and shielding. Current rating of 850 mA is lower than the original 1.4 A, limiting use to applications with reduced current demands. Extended temperature range to 130°C provides additional thermal margin. RoHS non-compliant status matches the original part. Footprint dimensions are marginally larger (7.37mm vs 7.30mm).

SCRH74-390 and SCRH74B-390 (Signal Transformer): Both parts offer identical electrical specifications with 910 mA current rating and 230 mOhm DC resistance matching the original. ROHS3 compliance provides regulatory advantage over the obsolete SPD74-393M. Operating temperature limited to -40°C minimum (versus -55°C original). Footprint dimensions are larger at 7.80mm x 7.80mm, requiring PCB layout verification. Height is reduced to 4.50mm, offering space savings in vertical direction.

SRR0745A-390M (Bourns Inc.): Highest current rating at 1.17 A with superior DC resistance of 190 mOhm maximum. Ferrite core and shielding match original specifications. ROHS3 compliant with AEC-Q200 automotive qualification. Footprint dimensions (7.30mm x 7.30mm) and height (4.70mm) are identical to the original SPD74-393M, enabling direct mechanical substitution. Operating temperature range -40°C to 125°C covers standard industrial requirements. Highest inventory availability (6886 pcs) ensures supply continuity.

Frequently Asked Questions (FAQ)

Q: Can HRSPD74-393M replace SPD74-393M in all applications?

A: HRSPD74-393M is suitable only for applications where circuit current does not exceed 850 mA. The original SPD74-393M is rated for 1.4 A. Verify actual circuit current requirements before substitution.

Q: Why are SCRH74-390 and SCRH74B-390 larger in footprint?

A: Both Signal Transformer parts measure 7.80mm x 7.80mm compared to the original 7.30mm x 7.30mm. PCB layout must accommodate this 0.50mm increase in both length and width dimensions. Height is reduced to 4.50mm, providing vertical clearance advantage.

Q: What is the primary advantage of SRR0745A-390M?

A: SRR0745A-390M offers identical mechanical footprint and height to the original SPD74-393M (7.30mm x 7.30mm x 4.70mm), enabling direct PCB substitution without layout modification. Current rating of 1.17 A and DC resistance of 190 mOhm provide performance within acceptable range of the original 1.4 A and 230 mOhm specifications.

Q: Are all substitutes RoHS compliant?

A: SCRH74-390, SCRH74B-390, and SRR0745A-390M are ROHS3 compliant. HRSPD74-393M and the original SPD74-393M are RoHS non-compliant. Regulatory requirements determine compliance necessity for your application.

Q: What is the minimum operating temperature for each substitute?

A: HRSPD74-393M operates to -55°C, matching the original. SCRH74-390, SCRH74B-390, and SRR0745A-390M operate to -40°C minimum. Applications requiring -55°C operation must use HRSPD74-393M or the original part.

Q: Can substitutes be used interchangeably on the same PCB?

A: No. Footprint differences require PCB-specific evaluation. SRR0745A-390M and SPD74-393M share identical dimensions (7.30mm x 7.30mm x 4.70mm) and are mechanically interchangeable. HRSPD74-393M (7.37mm x 7.37mm) and SCRH74-390/SCRH74B-390 (7.80mm x 7.80mm) require layout verification before use.

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