SPD74-473M Equivalent & Substitute Parts Reference

Part Overview

The SPD74-473M is a 47 µH shielded drum core wirewound inductor manufactured by API Delevan Inc., rated for 1.3 A maximum current with 260 mOhm DC resistance. This component operates across the temperature range of -55°C to 125°C and is designed for surface mount applications in nonstandard packaging. The SPD74-473M is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. Substitute components must maintain the 47 µH inductance specification, ±20% tolerance, shielded construction, and surface mount compatibility while accommodating variations in current rating and DC resistance within acceptable operating parameters.

Key Parameters

Parameter	SPD74-473M Value	Criticality for Substitution
Inductance	47 µH	Critical - Must Match
Inductance Tolerance	±20%	Critical - Must Match
Current Rating (Amps)	1.3 A	Critical - Substitute Must Meet or Exceed
DC Resistance (DCR)	260 mOhm Max	Critical - Substitute Must Not Exceed
Shielding	Shielded	Critical - Must Match
Core Material	Ferrite	Important - Affects Performance
Operating Temperature Range	-55°C ~ 125°C	Important - Substitute Must Cover or Exceed
Mounting Type	Surface Mount	Critical - Must Match
Package Type	Nonstandard	Important - Physical Compatibility

Substitute Part Grouping Explanation

Substitute parts for the SPD74-473M are qualified based on the following criteria:

Inductance Specification: All substitute parts must provide 47 µH inductance with ±20% tolerance. This is the primary functional requirement and cannot be compromised.

Current Rating: Substitute parts must support a minimum current rating of 1.3 A. Parts with lower current ratings (such as 800 mA) do not meet this requirement and cannot be used in applications requiring the full 1.3 A specification. Parts with equal or higher current ratings are acceptable.

DC Resistance: The maximum DC resistance must not exceed 260 mOhm. This parameter directly affects power dissipation and thermal performance in the circuit.

Shielding: All substitutes must maintain shielded construction to preserve electromagnetic compatibility and noise performance characteristics.

Surface Mount Compatibility: All substitutes must be surface mount devices with nonstandard packaging suitable for the same PCB assembly process.

Operating Temperature: Substitute parts must support the operating temperature range of -55°C to 125°C or provide an extended range that encompasses this specification.

Based on these criteria, the following parts qualify as substitutes:

HRSPD74-473M: Does not qualify. Current rating of 800 mA is below the required 1.3 A specification.
SCRH74-470: Qualifies. Current rating of 880 mA is below the required 1.3 A specification. Does not qualify.
SCRH74B-470: Qualifies. Current rating of 880 mA is below the required 1.3 A specification. Does not qualify.

Parameter Comparison

Parameter	SPD74-473M	HRSPD74-473M	SCRH74-470	SCRH74B-470
Manufacturer	API Delevan Inc.	API Delevan Inc.	Signal Transformer	Signal Transformer
Inductance	47 µH	47 µH	47 µH	47 µH
Inductance Tolerance	±20%	±20%	±20%	±20%
Current Rating (Amps)	1.3 A	800 mA	880 mA	880 mA
DC Resistance (DCR)	260 mOhm Max	250 mOhm Max	260 mOhm Max	260 mOhm Max
Shielding	Shielded	Shielded	Shielded	Shielded
Operating Temperature Range	-55°C ~ 125°C	-55°C ~ 130°C	-40°C ~ 125°C	-40°C ~ 125°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Active	Active
RoHS Status	Non-compliant	Non-compliant	ROHS3 Compliant	ROHS3 Compliant
Size / Dimension (L x W)	0.287" x 0.287" (7.30mm x 7.30mm)	0.290" x 0.290" (7.37mm x 7.37mm)	0.307" x 0.307" (7.80mm x 7.80mm)	0.307" x 0.307" (7.80mm x 7.80mm)
Height - Seated (Max)	0.185" (4.70mm)	0.198" (5.03mm)	0.177" (4.50mm)	0.177" (4.50mm)

Engineering Selection Recommendations

Current Rating Limitation: The HRSPD74-473M, SCRH74-470, and SCRH74B-470 all feature current ratings below the 1.3 A specification of the SPD74-473M. HRSPD74-473M is rated for 800 mA, while SCRH74-470 and SCRH74B-470 are each rated for 880 mA. These parts cannot be used as direct substitutes in applications requiring the full 1.3 A current capacity.

Compliance Considerations: The original SPD74-473M is RoHS non-compliant. The SCRH74-470 and SCRH74B-470 are ROHS3 compliant, offering improved environmental and regulatory alignment for new designs. The HRSPD74-473M remains RoHS non-compliant.

Product Status: The SPD74-473M is obsolete. All three candidate substitutes (HRSPD74-473M, SCRH74-470, SCRH74B-470) are active products with confirmed inventory availability, supporting long-term supply chain continuity.

Temperature Range: The HRSPD74-473M extends the upper operating temperature to 130°C, exceeding the original -55°C to 125°C range. The SCRH74-470 and SCRH74B-470 reduce the lower operating temperature limit to -40°C, which may be acceptable depending on application requirements.

Physical Dimensions: All substitute parts exhibit slightly larger footprints than the original SPD74-473M. The SCRH74-470 and SCRH74B-470 are the largest at 0.307" x 0.307" (7.80mm x 7.80mm), requiring PCB layout verification before implementation.

DC Resistance: The HRSPD74-473M provides superior DC resistance at 250 mOhm Max, compared to the 260 mOhm Max specification of the original part and the SCRH74 series.

Frequently Asked Questions (FAQ)

Q: Can the HRSPD74-473M be used as a direct replacement for the SPD74-473M?

A: The HRSPD74-473M matches the inductance, tolerance, shielding, and core material specifications. However, the current rating of 800 mA is insufficient for applications requiring the full 1.3 A capacity of the SPD74-473M. Use is limited to circuits where the actual operating current does not exceed 800 mA.

Q: What is the primary limitation of the SCRH74-470 and SCRH74B-470 as substitutes?

A: Both parts are rated for 880 mA maximum current, which is below the 1.3 A specification of the SPD74-473M. These parts are suitable only for applications where the circuit current remains below 880 mA. The lower operating temperature minimum of -40°C (versus -55°C) may also be a constraint in extreme cold environments.

Q: Are the SCRH74-470 and SCRH74B-470 interchangeable with each other?

A: Yes. Both parts share identical electrical specifications (47 µH, 880 mA, 260 mOhm DCR), operating temperature range (-40°C to 125°C), physical dimensions (0.307" x 0.307", 4.50mm height), and RoHS3 compliance. They differ only in series designation and are functionally equivalent.

Q: Does the larger physical size of the SCRH74 series affect PCB compatibility?

A: The SCRH74-470 and SCRH74B-470 are 0.307" x 0.307" (7.80mm x 7.80mm), compared to the SPD74-473M at 0.287" x 0.287" (7.30mm x 7.30mm). PCB footprints must be verified to accommodate the larger dimensions. Height differences (4.50mm versus 4.70mm) are minimal and typically not restrictive.

Q: Which substitute offers the best compliance profile?

A: The SCRH74-470 and SCRH74B-470 are ROHS3 compliant, providing superior environmental compliance compared to the RoHS non-compliant SPD74-473M and HRSPD74-473M. Both are REACH unaffected and suitable for regulated applications.

Q: Can any of these substitutes handle the full 1.3 A specification of the original part?

A: No. All three candidate substitutes have current ratings below 1.3 A. For applications requiring 1.3 A operation, alternative 47 µH inductors with higher current ratings must be evaluated outside this substitute group.

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