SPD125-183M Equivalent & Substitute Parts

Part Overview

The SPD125-183M is a 18 µH shielded inductor manufactured by API Delevan Inc., rated for 3 A continuous current with a maximum DC resistance of 70mOhm. This component is designed for surface mount applications in nonstandard package configurations. The part is currently classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement planning.

Substiute Parts

SPD125-183M

API Delevan Inc.In Stock: 1077SPD125-183M Datasheet

Current PartRFQ

SRR1206-180ML

Bourns Inc.In Stock: 3397SRR1206-180ML Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SPD125-183M is determined by the following critical parameters:

Primary Matching Criteria:

• Inductance value: 18 µH (±20% tolerance band)
• Core material: Ferrite shielded construction
• Mounting technology: Surface mount
• Physical footprint compatibility: Nonstandard package within acceptable dimensional variance

Secondary Compatibility Factors:

• Current rating: Minimum 2.5 A (acceptable for applications rated up to 3 A with thermal margin analysis)
• DC resistance: Maximum 50mOhm to 70mOhm range
• Operating temperature: Overlap within -40°C to 125°C minimum

The SRR1206-180ML from Bourns Inc. meets these substitution criteria through matching inductance specification, ferrite core construction, shielded design, and surface mount configuration.

Parameter Comparison

Engineering Selection Recommendations

Substitution Feasibility:

The SRR1206-180ML is a valid functional equivalent for the SPD125-183M based on matched inductance value, ferrite core construction, shielded design, and surface mount technology. The substitute part is currently in active production status, ensuring long-term availability compared to the obsolete main part.

Compliance Advantages:

The SRR1206-180ML provides ROHS3 compliance, addressing regulatory requirements that may not be met by the RoHS non-compliant SPD125-183M. This compliance status is significant for applications subject to environmental and hazardous substance restrictions.

Current Rating Consideration:

The substitute part carries a 2.5 A continuous current rating versus the main part's 3 A rating. Applications operating at or near the 3 A maximum must evaluate thermal performance and duty cycle requirements. The substitute's saturation current of 4.7 A provides margin above the continuous rating.

Dimensional Compatibility:

Physical footprint increases of 0.70mm in length, width, and 0.50mm in height must be verified against PCB layout constraints and mechanical clearance requirements. Nonstandard package configurations require case-by-case dimensional validation.

Temperature Range:

The substitute part's operating range of -40°C to 125°C is narrower at the low temperature extreme compared to the main part's -55°C specification. Applications requiring operation below -40°C cannot use this substitute without additional thermal analysis.

Frequently Asked Questions (FAQ)

Q: Can the SRR1206-180ML directly replace the SPD125-183M in all applications?

A: Direct replacement requires verification of three factors: (1) continuous current demand not exceeding 2.5 A, (2) minimum operating temperature not below -40°C, and (3) PCB layout accommodation of the 0.70mm dimensional increase in footprint and 0.50mm height increase.

Q: What is the significance of the different current ratings?

A: The main part SPD125-183M is rated for 3 A continuous current, while the substitute SRR1206-180ML is rated for 2.5 A. Applications designed for 3 A operation must confirm that actual operating current remains within the 2.5 A substitute rating, or implement thermal derating analysis.

Q: How do the DC resistance values affect substitution?

A: The substitute part's 50mOhm maximum DC resistance is superior to the main part's 70mOhm maximum. Lower resistance reduces power dissipation and heat generation, providing a performance advantage in this parameter.

Q: Are there packaging differences between these parts?

A: Yes. The SPD125-183M uses a nonstandard package configuration, while the SRR1206-180ML is supplied in Tape & Reel (TR) format. Procurement and assembly processes may require adjustment to accommodate the different packaging standard.

Q: What is the impact of RoHS compliance differences?

A: The main part is RoHS non-compliant, while the substitute is ROHS3 compliant. For applications subject to RoHS regulations or customer requirements, the substitute provides regulatory alignment. Non-regulated applications may use either part based on technical compatibility alone.

Q: How should the saturation current difference be interpreted?

A: The main part saturates at 3 A, while the substitute saturates at 4.7 A. The substitute provides greater saturation margin above its 2.5 A continuous rating, indicating more stable performance under transient current conditions within its rated envelope.

Q: Is the inductance tolerance identical between parts?

A: Yes. Both parts specify ±20% inductance tolerance at 1 kHz test frequency, ensuring equivalent inductance accuracy and circuit performance predictability.