SPD73R-273M Equivalent & Substitute Parts

Part Overview

The SPD73R-273M is a 27 µH shielded drum core wirewound inductor manufactured by API Delevan Inc., designed for surface mount applications requiring moderate current handling and low DC resistance. This component operates across an industrial temperature range of -55°C to 125°C and maintains active product status with full RoHS3 compliance. Substitute parts are identified when equivalent electrical performance can be achieved within the specified parameter tolerances while maintaining mechanical compatibility with the mounting footprint.

Key Parameters

Parameter	Value	Unit	Significance for Substitution
Inductance	27	µH	Primary electrical specification; must match exactly
Current Rating (Continuous)	1.6	A	Determines thermal and saturation performance; substitute must meet or exceed
DC Resistance (DCR)	210	mOhm Max	Affects power dissipation and efficiency; lower values preferred
Saturation Current (Isat)	1.6	A	Defines maximum usable current before inductance degradation
Shielding	Shielded	—	Electromagnetic interference containment; must be maintained
Mounting Type	Surface Mount	—	PCB assembly compatibility
Package Footprint	7.30 × 7.30 mm	mm	Physical placement on PCB; must be identical
Height (Seated Max)	3.90	mm	Clearance and assembly constraint; substitute height must not exceed main part
Operating Temperature Range	-55 to 125	°C	Application environment compatibility
Tolerance	±20	%	Inductance accuracy specification
RoHS Status	ROHS3 Compliant	—	Regulatory compliance requirement

Substitute Part Grouping Explanation

Substitution eligibility for the SPD73R-273M is determined by strict adherence to the following criteria:

Mandatory Matching Parameters:

Inductance value: 27 µH (exact match required)
Shielding type: Shielded (electromagnetic containment must be preserved)
Mounting type: Surface Mount (PCB assembly compatibility)
Package footprint: 7.30 × 7.30 mm (physical placement constraint)
Tolerance: ±20% (inductance accuracy class)
RoHS3 compliance (regulatory requirement)

Performance Parameters (Substitute Must Meet or Exceed):

Current Rating: Substitute minimum 1.6 A continuous
Saturation Current (Isat): Substitute minimum 1.6 A
DC Resistance: Lower values acceptable; maximum 210 mOhm preferred but not mandatory if other parameters are superior
Operating Temperature: Substitute range must encompass or exceed -55°C to 125°C

Physical Constraint:

Height (Seated Max): Substitute must not exceed 3.90 mm to ensure PCB clearance compatibility

The SRR0745A-270M from Bourns Inc. qualifies as a substitute based on matching inductance (27 µH), identical footprint (7.30 × 7.30 mm), shielded construction, surface mount configuration, ±20% tolerance, and RoHS3 compliance. Performance advantages include lower DC resistance (130 mOhm vs. 210 mOhm) and higher saturation current (1.62 A vs. 1.6 A), though the continuous current rating is slightly lower at 1.45 A.

Parameter Comparison

Parameter	SPD73R-273M (API Delevan)	SRR0745A-270M (Bourns)	Compatibility Status
Inductance	27 µH	27 µH	Match
Tolerance	±20%	±20%	Match
Current Rating	1.6 A	1.45 A	Substitute lower by 0.15 A
Saturation Current (Isat)	1.6 A	1.62 A	Substitute higher by 0.02 A
DC Resistance (Max)	210 mOhm	130 mOhm	Substitute lower by 80 mOhm (38% reduction)
Shielding	Shielded	Shielded	Match
Mounting Type	Surface Mount	Surface Mount	Match
Package Footprint	7.30 × 7.30 mm	7.30 × 7.30 mm	Match
Height (Seated Max)	3.90 mm	4.70 mm	Substitute higher by 0.80 mm
Operating Temperature	-55 to 125°C	-40 to 125°C	Substitute range narrower by 15°C at lower end
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Match
Moisture Sensitivity (MSL)	1 (Unlimited)	1 (Unlimited)	Match
REACH Status	REACH Unaffected	REACH Unaffected	Match

Engineering Selection Recommendations

Primary Part Selection (SPD73R-273M): Select the SPD73R-273M when the application requires the full operating temperature range of -55°C to 125°C and when the maximum seated height of 3.90 mm is a critical PCB assembly constraint. This part maintains active product status with established supply chain availability (1080 pcs in stock). The higher DC resistance of 210 mOhm is acceptable for applications where thermal dissipation is not a limiting factor.

Substitute Part Selection (SRR0745A-270M): The SRR0745A-270M from Bourns Inc. is electrically compatible when the application operating temperature does not require operation below -40°C. This substitute offers significant advantages in power efficiency due to 38% lower DC resistance (130 mOhm vs. 210 mOhm), resulting in reduced thermal dissipation and improved circuit efficiency. The substitute maintains identical inductance, footprint, shielding, and tolerance specifications. However, the increased seated height of 4.70 mm (0.80 mm taller) must be evaluated against PCB clearance requirements. The continuous current rating of 1.45 A is 0.15 A lower than the primary part; applications requiring sustained currents above 1.45 A should retain the SPD73R-273M. Both parts carry AEC-Q200 automotive qualification on the substitute, providing additional reliability assurance for demanding applications.

Compliance Verification: Both parts maintain ROHS3 compliance, REACH unaffected status, and MSL 1 (unlimited moisture sensitivity level), ensuring regulatory compatibility across industrial and commercial applications.

Frequently Asked Questions (FAQ)

Q: Can the SRR0745A-270M be used as a direct replacement for the SPD73R-273M in all applications?

A: The SRR0745A-270M is electrically compatible for inductance and shielding performance. However, three factors require evaluation: (1) Operating temperature—if your application requires operation below -40°C, the SPD73R-273M is required; (2) PCB clearance—the substitute is 0.80 mm taller (4.70 mm vs. 3.90 mm seated height); (3) Current rating—if sustained currents exceed 1.45 A, the SPD73R-273M's 1.6 A rating is necessary.

Q: What is the significance of the lower DC resistance in the SRR0745A-270M?

A: The 80 mOhm reduction in DC resistance (from 210 mOhm to 130 mOhm) directly reduces resistive power dissipation. In a 1.45 A application, this represents approximately 0.11 W less heat generation, improving circuit efficiency and reducing thermal stress on surrounding components.

Q: Are both parts suitable for automotive applications?

A: Both parts are RoHS3 compliant and REACH unaffected. The SRR0745A-270M carries AEC-Q200 automotive qualification, providing additional reliability assurance for automotive environments. The SPD73R-273M does not list AEC-Q200 qualification in the provided specifications.

Q: What is the inductance tolerance, and does it affect substitution?

A: Both parts specify ±20% inductance tolerance at 1 kHz test frequency. This tolerance is identical and does not create substitution barriers. At 27 µH nominal, the tolerance band spans 21.6 µH to 32.4 µH for both parts.

Q: Can I use the SRR0745A-270M if my PCB has limited vertical clearance?

A: No. If your PCB design requires a maximum seated height of 3.90 mm, the SRR0745A-270M at 4.70 mm will not fit. The SPD73R-273M must be retained in this case.

Q: What is the difference between current rating and saturation current?

A: Current rating (1.6 A for SPD73R-273M, 1.45 A for SRR0745A-270M) is the continuous current the inductor can handle without excessive temperature rise. Saturation current (Isat) is the peak current at which inductance begins to degrade significantly. The SRR0745A-270M has a higher Isat (1.62 A) despite a lower continuous rating, indicating superior saturation performance.

Q: Are there any packaging or supply chain differences?

A: Both parts are supplied in Tape & Reel (TR) packaging suitable for automated PCB assembly. The SPD73R-273M has 1080 pcs in stock; the SRR0745A-270M has 1211 pcs in stock, indicating comparable availability.

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