SPD73-273M Equivalent and Substitute Parts

Part Overview

The SPD73-273M is a 27 µH shielded drum core wirewound inductor manufactured by API Delevan Inc., rated for 1.05 A with a maximum DC resistance of 210mOhm. The component operates across a temperature range of -55°C to 125°C and is designed for surface mount applications in nonstandard package configurations. This part is currently obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and design continuity.

Key Parameters

Parameter	Value
Inductance	27 µH
Current Rating	1.05 A
DC Resistance (DCR)	210mOhm Max
Tolerance	±20%
Shielding	Shielded
Operating Temperature	-55°C to 125°C
Mounting Type	Surface Mount
Inductance Test Frequency	1 kHz
RoHS Status	Non-compliant

Substitute Part Grouping Explanation

Substitution of the obsolete SPD73-273M requires equivalence in the following critical parameters: inductance value (27 µH), tolerance (±20%), shielding type, DC resistance (210mOhm maximum), current rating capability, operating temperature range, and mounting method (surface mount, nonstandard package). All substitute parts identified meet the core inductance and resistance specifications. However, substitute parts vary in current rating capabilities and operating temperature minima, which affect their application suitability within system constraints.

Parameter Comparison

Parameter	SPD73-273M (Main)	SCB73C-270	SCPH73-270	SCPH73B-270	SCRH73B-270	SRR0745A-270M
Manufacturer	API Delevan Inc.	Signal Transformer	Signal Transformer	Signal Transformer	Signal Transformer	Bourns Inc.
Inductance	27 µH	27 µH	27 µH	27 µH	27 µH	27 µH
Tolerance	±20%	±20%	±20%	±20%	±20%	±20%
Current Rating (Amps)	1.05 A	1.46 A	1.3 A	1.3 A	960 mA	1.45 A
DC Resistance (DCR)	210mOhm Max	210mOhm Max	210mOhm Max	210mOhm Max	210mOhm Max	130mOhm Max
Shielding	Shielded	Shielded	Shielded	Shielded	Shielded	Shielded
Operating Temperature (Min)	-55°C	-40°C	-40°C	-40°C	-40°C	-40°C
Operating Temperature (Max)	125°C	125°C	125°C	125°C	125°C	125°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Active	Active	Active	Active	Active

Engineering Selection Recommendations

SCB73C-270, SCPH73-270, SCPH73B-270, and SCRH73B-270 are all active Signal Transformer products meeting the 27 µH inductance and 210mOhm maximum DC resistance specifications. These four alternatives are ROHS3 compliant with moisture sensitivity level 1 (unlimited), providing environmental performance advantages over the obsolete SPD73-273M.

SRR0745A-270M from Bourns Inc. offers superior DC resistance (130mOhm maximum) and is ROHS3 compliant with AEC-Q200 certification for automotive-grade reliability. This alternative provides the lowest DC resistance among all substitutes.

All substitute parts operate within the maximum temperature range (-40°C to 125°C) specified by the original part, with the exception of the minimum temperature threshold. The SPD73-273M extends to -55°C, while all substitutes support only -40°C minimum. Applications requiring operation below -40°C require specific evaluation.

SCRH73B-270 features the lowest current rating (960 mA), which approaches the minimum threshold of the original 1.05 A specification. Applications operating near the original current rating require margin analysis with this substitute.

Frequently Asked Questions (FAQ)

Q: Can SCRH73B-270 replace SPD73-273M in high current applications? A: SCRH73B-270 is rated for 960 mA with 960 mA saturation current, operating below the SPD73-273M's 1.05 A rating. Substitution is limited to applications with current margins below 960 mA.

Q: Which substitute offers the best DC resistance performance? A: SRR0745A-270M provides 130mOhm maximum DC resistance, significantly lower than the 210mOhm specification of all other alternatives and the original part.

Q: Are all substitutes compatible with the original nonstandard package? A: All substitute parts use surface mount installation with nonstandard package configurations. Physical dimensions vary slightly among alternatives (ranging from 7.30mm to 7.80mm lateral dimension and 3.50mm to 4.70mm height). Mechanical fit verification is required prior to assembly.

Q: What is the impact of the -40°C minimum operating temperature on substitutes? A: The original SPD73-273M operates to -55°C, while all substitutes have a -40°C minimum. Applications requiring operation below -40°C cannot use these substitutes.

Q: Which substitute provides modern compliance standards? A: All five substitute parts are ROHS3 compliant with REACH unaffected status. SRR0745A-270M additionally carries AEC-Q200 automotive-grade certification.

Q: Can multiple substitutes be used interchangeably in the same design? A: Substitutes differ in current rating (960 mA to 1.46 A), DC resistance (130mOhm to 210mOhm), and physical dimensions. Design-specific current, thermal, and mechanical constraints determine which substitute is appropriate for each application.

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