SPD73-684M Equivalent & Substitute Parts

Part Overview

The SPD73-684M is a 680 µH shielded drum core wirewound inductor manufactured by API Delevan Inc., designed for surface mount applications with a current rating of 201 mA and maximum DC resistance of 5.73Ohm. This component operates across the temperature range of -55°C to 125°C and is classified as obsolete product status.

Due to the obsolete status of the SPD73-684M, locating equivalent substitute components is necessary for ongoing production, maintenance, and design continuity. Substitute parts must maintain electrical compatibility while meeting current manufacturing and compliance standards.

Substiute Parts

SPD73-684M

API Delevan Inc.In Stock: 844SPD73-684M Datasheet

Current PartRFQ

SRR0745A-681M

Bourns Inc.In Stock: 1278SRR0745A-681M Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the SPD73-684M are identified based on strict electrical and mechanical parameter alignment. The following criteria determine substitution eligibility:

Primary Electrical Parameters:

• Inductance value: 680 µH (matching specification)
• Inductance tolerance: ±20% (matching specification)
• Shielding type: Shielded (matching specification)
• Core material: Ferrite (matching specification)
• Inductance test frequency: 1 kHz (matching specification)

Current and Thermal Parameters:

• Current rating must equal or exceed 201 mA
• Saturation current (Isat) must equal or exceed 201 mA
• Operating temperature range must encompass or exceed -55°C to 125°C

Mechanical Parameters:

• Mounting type: Surface Mount (matching specification)
• Package dimensions: 7.30mm x 7.30mm footprint (matching specification)
• Height must be compatible with PCB assembly constraints

The SRR0745A-681M from Bourns Inc. meets all substitution criteria with improved electrical performance characteristics and active product status.

Parameter Comparison

Engineering Selection Recommendations

The SRR0745A-681M from Bourns Inc. is the qualified substitute for the obsolete SPD73-684M. Selection is based on the following engineering factors:

Electrical Compatibility: The substitute part maintains identical inductance value (680 µH) and tolerance (±20%) at the specified test frequency of 1 kHz. Current rating and saturation current specifications of the substitute exceed the original part requirements, providing design margin.

Thermal Performance: The substitute operates across -40°C to 125°C. Applications requiring the full -55°C lower temperature limit of the original part must conduct thermal validation.

Compliance Status: The SRR0745A-681M holds active product status with ROHS3 compliance and AEC-Q200 certification, ensuring long-term availability and automotive-grade reliability. The original SPD73-684M is RoHS non-compliant and obsolete.

Mechanical Fit: Both parts share identical footprint dimensions (7.30mm x 7.30mm). The substitute height of 4.70mm exceeds the original 3.90mm maximum. PCB assembly clearance must be verified for applications with height constraints.

DC Resistance Improvement: The substitute exhibits significantly lower DC resistance (2.8Ohm Max versus 5.73Ohm Max), resulting in reduced power dissipation and improved thermal performance in the application circuit.

Frequently Asked Questions (FAQ)

Q: Can the SRR0745A-681M directly replace the SPD73-684M without circuit modification?

A: The SRR0745A-681M is electrically compatible for applications operating within -40°C to 125°C. Applications requiring operation below -40°C require thermal analysis. The substitute's lower DC resistance and higher current rating provide improved performance margins. PCB assembly height clearance must be verified due to the 0.80mm height increase.

Q: What is the significance of the current rating and saturation current specifications?

A: Current rating (201 mA for original, 240 mA for substitute) defines continuous operating current. Saturation current (Isat) defines the current level at which inductance begins to degrade. The substitute's higher specifications (240 mA / 280 mA) ensure the component operates with greater design margin in the application circuit.

Q: Why is DC resistance important in inductor substitution?

A: DC resistance directly affects power dissipation (P = I²R) and thermal performance. The substitute's 2.8Ohm maximum resistance versus the original 5.73Ohm represents approximately 51% lower dissipation at rated current, improving efficiency and reducing heat generation.

Q: Are there packaging differences between the original and substitute?

A: The original SPD73-684M uses nonstandard packaging. The SRR0745A-681M is supplied in Tape & Reel (TR) format, standard for high-volume surface mount assembly. Both maintain identical 7.30mm x 7.30mm footprint dimensions.

Q: What compliance certifications apply to the substitute part?

A: The SRR0745A-681M holds AEC-Q200 automotive qualification, ROHS3 compliance, and Moisture Sensitivity Level (MSL) 1 rating. These certifications ensure suitability for automotive and industrial applications with long-term supply assurance.

Q: How does the operating temperature range affect substitution decisions?

A: The original part operates -55°C to 125°C; the substitute operates -40°C to 125°C. Applications with minimum operating temperatures at or above -40°C are fully compatible. Applications requiring -55°C operation must validate substitute performance through thermal testing or select alternative components.