SPD73-183M Equivalent & Substitute Parts

Part Overview

The SPD73-183M is an 18 µH shielded drum core, wirewound inductor manufactured by API Delevan Inc., rated for 1.28 A with a maximum DC resistance of 140 mOhm. This component features ferrite core construction, surface mount packaging, and operates across the temperature range of -55°C to 125°C. The part is classified as obsolete, making alternative components necessary for new designs and procurement planning.

Key Parameters

Parameter	Value
Inductance	18 µH
Tolerance	±20%
Current Rating (Amps)	1.28 A
DC Resistance (DCR) Max	140 mOhm
Shielding	Shielded
Operating Temperature	-55°C ~ 125°C
Mounting Type	Surface Mount
Size / Dimension	0.287" L x 0.287" W (7.30mm x 7.30mm)
Height - Seated (Max)	0.154" (3.90mm)
Inductance Frequency - Test	1 kHz

Substitute Part Grouping Explanation

Substitute parts for the SPD73-183M are selected based on the following critical parameters that determine electrical and mechanical compatibility:

Electrical Parameters:

Inductance value: 18 µH (fixed requirement)
Tolerance: ±20% (all substitutes comply)
DC Resistance: Maximum 140 mOhm (tolerance allows variations within this limit)
Shielding: Shielded construction (all substitutes maintain electromagnetic shielding)
Mounting: Surface mount (all alternatives are surface mount compatible)

Mechanical Parameters:

Package footprint: 7.30mm x 7.30mm nominal (CDRH73NP and SRR0745A match; SCRH73/SCRH73B vary at 7.80mm)
Height clearance: Maximum seated height consideration for board layout
Temperature range: Operating temperature span from -55°C to 125°C minimum

Current Rating Considerations: Substitutes include parts rated for 1.2 A, 1.8 A, and 1.95 A saturation current. Selection depends on application current requirements:

1.2 A parts (CDRH73NP-180MC-B, SCRH73-180, SCRH73B-180): Suitable for designs requiring ≤1.2 A
1.8 A parts (SPD73R-183M, SRR0745A-180M): Suitable for designs requiring ≤1.8 A

Parameter Comparison

Part Number	Manufacturer	Inductance	Current Rating (A)	DCR Max (mOhm)	Shielded	Footprint (mm)	Height Max (mm)	Temp Range (°C)	RoHS Status	Product Status
SPD73-183M	API Delevan Inc.	18 µH	1.28	140	Shielded	7.30 x 7.30	3.90	-55 to 125	Non-compliant	Obsolete
SPD73R-183M	API Delevan Inc.	18 µH	1.8	140	Shielded	7.30 x 7.30	3.90	-55 to 125	ROHS3 Compliant	Active
CDRH73NP-180MC-B	Sumida America Components Inc.	18 µH	1.2	140	Shielded	7.30 x 7.30	3.40	-40 to 100	ROHS3 Compliant	Active
SCRH73-180	Signal Transformer	18 µH	1.2	140	Shielded	7.80 x 7.80	3.50	-40 to 125	ROHS3 Compliant	Active
SCRH73B-180	Signal Transformer	18 µH	1.2	140	Shielded	7.80 x 7.80	3.50	-40 to 125	ROHS3 Compliant	Active
SRR0745A-180M	Bourns Inc.	18 µH	1.8	90	Shielded	7.30 x 7.30	4.70	-40 to 125	ROHS3 Compliant	Active

Engineering Selection Recommendations

Primary Recommended Substitute: SPD73R-183M

The SPD73R-183M from API Delevan Inc. is the direct upgrade path from the obsolete SPD73-183M. This part maintains identical electrical specifications (18 µH, 140 mOhm DCR), identical mechanical footprint (7.30 x 7.30 mm), and identical thermal operating range (-55°C to 125°C). The higher current rating of 1.8 A provides additional design margin. The SPD73R-183M is ROHS3 compliant with active product status and available inventory of 2043 units.

Secondary Options by Application Current Requirements:

For applications with current budgets of 1.8 A or higher: The SRR0745A-180M from Bourns Inc. offers superior DC resistance performance at 90 mOhm maximum (versus 140 mOhm), reducing heat dissipation. This part carries AEC-Q200 automotive qualification and ROHS3 compliance. The tradeoff is increased height (4.70 mm versus 3.90 mm) which requires board layout clearance verification.

For applications with current budgets limited to 1.2 A: Both CDRH73NP-180MC-B from Sumida and SCRH73-180 or SCRH73B-180 from Signal Transformer provide cost-effective alternatives. The CDRH73NP-180MC-B matches the original footprint exactly (7.30 x 7.30 mm) with reduced height (3.40 mm). The Signal Transformer parts feature extended temperature operation to -40°C minimum and reduced height (3.50 mm) but require footprint accommodation of 7.80 x 7.80 mm.

All active substitutes carry ROHS3 compliance and unlimited moisture sensitivity level rating (MSL 1).

Frequently Asked Questions (FAQ)

Q: Can SPD73R-183M be used as a direct replacement for SPD73-183M?

A: Yes, the SPD73R-183M is the direct replacement. It maintains all critical electrical parameters (18 µH inductance, ±20% tolerance, 140 mOhm DCR, -55°C to 125°C operation), identical mechanical footprint (7.30 x 7.30 mm), and mounting type. The increased current rating from 1.28 A to 1.8 A provides additional performance margin and does not create compatibility issues.

Q: What are the key differences between the 1.2 A and 1.8 A rated substitutes?

A: Current rating determines the maximum DC current the inductor can handle before saturation. The 1.28 A original and 1.8 A alternatives (SPD73R-183M, SRR0745A-180M) suit higher-current applications. The 1.2 A alternatives (CDRH73NP-180MC-B, SCRH73-180, SCRH73B-180) suit applications with lower current budgets or cost-sensitive designs. All substitutes maintain the same 18 µH inductance value and ±20% tolerance.

Q: How does footprint size affect component selection?

A: The original SPD73-183M and most substitutes maintain a 7.30 x 7.30 mm footprint (SPD73R-183M, CDRH73NP-180MC-B, SRR0745A-180M). The Signal Transformer alternatives (SCRH73-180, SCRH73B-180) measure 7.80 x 7.80 mm, requiring larger board space but offering identical electrical specifications at 1.2 A rating. Height variations also require clearance verification: the original is 3.90 mm tall, while alternatives range from 3.40 mm to 4.70 mm.

Q: What is the significance of DCR (DC Resistance) differences?

A: The SPD73-183M and all substitutes except SRR0745A-180M specify 140 mOhm maximum DCR. The SRR0745A-180M offers lower 90 mOhm DCR, resulting in reduced resistive losses and heat generation in high-current applications. This advantage is balanced against a taller profile (4.70 mm) requiring board layout accommodation. DCR selection depends on thermal and efficiency requirements of the specific application.

Q: What does ROHS3 compliance mean for component sourcing?

A: All active substitutes carry ROHS3 compliance status, indicating they meet the Restriction of Hazardous Substances Directive (Phase 3). The original SPD73-183M is non-compliant due to its obsolete classification. ROHS3 compliance is standard for modern electronic components and aligns with environmental and regulatory requirements in most markets.

Q: Are all substitutes rated for -55°C to 125°C operation like the original?

A: The SPD73R-183M, SCRH73-180, SCRH73B-180, and SRR0745A-180M all operate across -55°C to 125°C or -40°C to 125°C temperature ranges, meeting or exceeding the original specification. The CDRH73NP-180MC-B operates from -40°C to 100°C, which is narrower than the original. Application thermal requirements must be verified against the selected substitute's operating temperature range.

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