SPD125-684M

Part Overview

The SPD125-684M is a 680 µH shielded inductor manufactured by API Delevan Inc., designed for surface mount applications with a 500 mA current rating and 1.3Ohm maximum DC resistance. This component is classified as obsolete, necessitating identification of active substitute parts to maintain supply chain continuity for existing designs and new production runs.

Substiute Parts

SPD125-684M

API Delevan Inc.In Stock: 829SPD125-684M Datasheet

Current PartRFQ

SRR1206-681KL

Bourns Inc.In Stock: 1984SRR1206-681KL Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SPD125-684M is based on the following critical electrical and mechanical parameters:

Electrical Matching Criteria:

• Inductance value: 680 µH (identical)
• Current rating: Minimum 500 mA required to handle the original design current
• DC resistance: Maximum 1.3Ohm preferred to maintain circuit performance
• Shielding: Shielded configuration required for electromagnetic isolation

Mechanical Matching Criteria:

• Mounting type: Surface Mount (SMD)
• Core material: Ferrite
• Package classification: Nonstandard form factor
• Physical footprint: Nominal 12.00mm x 12.00mm base dimensions

The SRR1206-681KL from Bourns Inc. qualifies as a functional substitute based on matching inductance, shielded ferrite core construction, surface mount configuration, and compatible form factor, despite variations in rated current, DC resistance, and temperature range.

Parameter Comparison

Engineering Selection Recommendations

The SRR1206-681KL represents the primary active substitute for the obsolete SPD125-684M. Selection of this substitute is supported by the following factors:

Product Status: The SRR1206-681KL is actively manufactured, ensuring ongoing availability and supply chain reliability, whereas the original SPD125-684M is classified as obsolete with no production continuation.

Regulatory Compliance: The SRR1206-681KL meets ROHS3 compliance standards, positioning the design for current and future regulatory requirements. The original part is RoHS non-compliant.

Electrical Compatibility: Both inductors provide 680 µH inductance with ferrite core construction and shielded configuration. The substitute exhibits tighter inductance tolerance (±10% versus ±20%), improving circuit performance consistency. The DC resistance variance (1.5Ohm Max versus 1.3Ohm Max) represents a 0.2Ohm differential, acceptable for most applications. The substitute's higher saturation current (700mA) provides headroom above the original 500mA rated current.

Physical Footprint: The substitute dimensions (12.70mm x 12.70mm x 6.50mm) represent marginal increases over the original (12.00mm x 12.00mm x 6.00mm), requiring board layout verification but generally compatible with existing designs.

Temperature Range: The substitute operates across -40°C to 125°C, narrower at the lower extreme than the original (-55°C to 125°C). Applications requiring operation below -40°C require alternative evaluation.

Frequently Asked Questions (FAQ)

Q: Can the SRR1206-681KL directly replace the SPD125-684M in existing designs?

A: The SRR1206-681KL provides functional electrical equivalence for most applications. Physical footprint verification is required due to marginal dimension increases. Applications with temperature operating points below -40°C require alternative consideration.

Q: What are the primary electrical differences between these inductors?

A: Both inductors maintain identical 680 µH inductance and ferrite shielded core design. Key differences include: the substitute exhibits ±10% tolerance (tighter than the original ±20%), lower rated current (400mA versus 500mA), marginally higher DC resistance (1.5Ohm versus 1.3Ohm), and higher saturation current (700mA). These differences are within acceptable parameters for most circuit applications.

Q: How do physical dimension differences impact PCB redesign requirements?

A: The SRR1206-681KL footprint (12.70mm x 12.70mm x 6.50mm) exceeds the original (12.00mm x 12.00mm x 6.00mm) by approximately 0.70mm in length and width, and 0.50mm in height. PCB layout review is required to confirm component clearance and trace routing compatibility. Package pinout compatibility must be verified against design documentation.

Q: Is regulatory compliance important for this substitution?

A: The substitute SRR1206-681KL meets ROHS3 standards, whereas the original is RoHS non-compliant. New production designs and applications subject to RoHS regulations must utilize compliant components. Existing RoHS-exempt applications may operate either part.

Q: What applications are suitable for the SRR1206-681KL substitute?

A: The substitute is suitable for power supply filtering, EMI suppression, energy storage in DC-DC converters, and general signal filtering applications requiring 680 µH inductance in the 400-700mA current range. Circuit current requirements must not exceed the substitute's 400mA rated current specification.