SPD73-124M Equivalent & Substitute Parts

Part Overview

The SPD73-124M is a 120 µH shielded drum core wirewound inductor manufactured by API Delevan Inc., rated for 524 mA with a maximum DC resistance of 840mOhm. This component is classified as obsolete, making identification of suitable substitute parts essential for ongoing design support and production continuity. The part operates across an industrial temperature range of -55°C to 125°C and is mounted as a surface mount device in a nonstandard 7.30mm × 7.30mm package footprint.

Substiute Parts

SPD73-124M

API Delevan Inc.In Stock: 1149SPD73-124M Datasheet

Current PartRFQ

SRR0745A-121M

Bourns Inc.In Stock: 3971SRR0745A-121M Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SPD73-124M is determined by the following critical parameters:

Primary Matching Criteria:

• Inductance value: 120 µH at 1 kHz test frequency
• Inductance tolerance: ±20%
• Core material: Ferrite with shielding
• Mounting type: Surface Mount
• Package footprint: 7.30mm × 7.30mm (identical physical dimensions)

Secondary Compatibility Criteria:

• Current rating must meet or exceed 524 mA
• DC resistance must not exceed 840 mOhm to maintain circuit performance
• Operating temperature range must encompass the application requirements
• Saturation current (Isat) must support the circuit's maximum current demands

The SRR0745A-121M from Bourns Inc. satisfies all primary matching criteria and demonstrates improved electrical performance in current rating and DC resistance characteristics.

Parameter Comparison

Engineering Selection Recommendations

The SRR0745A-121M is the qualified substitute for the obsolete SPD73-124M based on the following factors:

Electrical Compatibility: The substitute maintains identical inductance (120 µH) and tolerance (±20%) at the specified test frequency of 1 kHz. Current rating and saturation current both exceed the original specification, providing design margin. DC resistance is reduced by 34% (550 mOhm vs. 840 mOhm), resulting in lower power dissipation and improved thermal performance.

Physical Compatibility: Identical footprint dimensions (7.30mm × 7.30mm) ensure PCB layout compatibility. The substitute is 0.80 mm taller (4.70 mm vs. 3.90 mm seated height); verify clearance in the assembly envelope before implementation.

Product Status and Compliance: The SRR0745A-121M is actively manufactured by Bourns Inc., ensuring long-term availability and supply chain stability. The substitute is ROHS3 compliant and carries AEC-Q200 automotive qualification, meeting modern regulatory and quality standards that the obsolete original part does not.

Temperature Range Consideration: The substitute operating range (-40°C to 125°C) is narrower at the low temperature extreme compared to the original (-55°C to 125°C). Applications requiring operation below -40°C must retain the original part or identify alternative solutions.

Frequently Asked Questions (FAQ)

Q: Can the SRR0745A-121M directly replace the SPD73-124M without circuit modification?

A: Yes, for applications operating within -40°C to 125°C. The identical inductance value, tolerance, and core material ensure electrical equivalence. The improved current rating and lower DC resistance provide additional design margin. Verify PCB clearance for the 0.80 mm height increase.

Q: Why is the DC resistance lower in the substitute part?

A: The SRR0745A-121M uses optimized winding geometry and materials to achieve 550 mOhm maximum resistance compared to 840 mOhm in the original. This is a performance improvement that reduces I²R losses in the inductor.

Q: What is the significance of the AEC-Q200 certification on the substitute?

A: AEC-Q200 is an automotive industry qualification standard. This certification indicates the substitute has undergone rigorous testing for reliability, temperature cycling, and performance consistency. It is not required for non-automotive applications but demonstrates manufacturing quality.

Q: Does the height difference affect PCB assembly?

A: The substitute is 0.80 mm taller (4.70 mm vs. 3.90 mm). Verify clearance above the component for any overlying components, shielding cans, or conformal coating processes. If clearance is insufficient, the original part must be retained.

Q: Is the substitute available in the same packaging format?

A: The SRR0745A-121M is supplied in Tape & Reel (TR) packaging, which is standard for high-volume production. The original part packaging format is not specified in the available data. Confirm packaging requirements with your procurement process.

Q: What should I do if my application requires operation below -40°C?

A: The SRR0745A-121M is not rated below -40°C. If your application requires -55°C operation, the original SPD73-124M specification must be maintained, or alternative parts with extended low-temperature ratings must be evaluated.

Q: Are there any compliance implications when switching from the original to the substitute?

A: The substitute is ROHS3 compliant, whereas the original is RoHS non-compliant. If your product is subject to RoHS regulations, the substitute improves compliance status. Both parts are REACH Unaffected and classified as EAR99 for export control purposes.