PM125S-680M Equivalent & Substitute Parts

Part Overview

The PM125S-680M is a 68 µH shielded drum core, wirewound inductor manufactured by Bourns Inc., rated for 1.26 A with a maximum DC resistance of 170mOhm. This surface mount component operates across -40°C to 125°C and features ferrite core construction with ±20% inductance tolerance.

The PM125S-680M is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity and ensure component availability for production and repair applications.

Substiute Parts

PM125S-680M

Bourns Inc.In Stock: 1140PM125S-680M Datasheet

Current PartRFQ

SRR1205-680YL

Bourns Inc.In Stock: 738SRR1205-680YL Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

The SRR1205-680YL qualifies as a substitute for the PM125S-680M based on the following critical parameters:

• Identical inductance value: 68 µH
• Compatible current rating: 1.3 A (exceeds minimum 1.26 A requirement)
• Ferrite core construction with shielding maintained
• Identical operating temperature range: -40°C to 125°C
• Surface mount configuration preserved
• Nonstandard package type consistent with original design

The SRR1205-680YL represents an active product with improved specifications in saturation current (2.4 A vs. 2.08 A) and RoHS3 compliance, making it suitable for direct substitution in applications where the PM125S-680M is no longer available.

Parameter Comparison

Engineering Selection Recommendations

The SRR1205-680YL is the qualified substitute for the obsolete PM125S-680M. Selection is based on:

• Product status: SRR1205-680YL is active and in production, ensuring long-term availability
• Electrical equivalence: Inductance, current rating, and saturation current meet or exceed original specifications
• Environmental compliance: SRR1205-680YL achieves RoHS3 compliance, addressing regulatory requirements that the original part does not meet
• Thermal performance: Identical operating temperature range ensures thermal compatibility
• Physical form factor: Both components maintain nonstandard package configuration and surface mount mounting

The increased DC resistance (280mOhm vs. 170mOhm) and lower self resonant frequency (6.5 MHz vs. 9 MHz) in the SRR1205-680YL must be evaluated within the specific circuit application to confirm thermal and frequency response compatibility.

Frequently Asked Questions (FAQ)

Q: Can the SRR1205-680YL directly replace the PM125S-680M in existing designs?

A: The SRR1205-680YL meets the core electrical requirements for substitution: identical 68 µH inductance, compatible current rating (1.3 A vs. 1.26 A), and matching operating temperature range. However, the increased DC resistance and lower self resonant frequency require circuit-level evaluation to confirm performance equivalence in your specific application.

Q: What is the significance of the higher DC resistance in the SRR1205-680YL?

A: The SRR1205-680YL has a maximum DC resistance of 280mOhm compared to 170mOhm in the PM125S-680M. This difference will result in increased power dissipation at rated current. Thermal analysis of your circuit is necessary to determine if this variance is acceptable for your application.

Q: How do the self resonant frequencies differ between these parts?

A: The PM125S-680M has a self resonant frequency of 9 MHz, while the SRR1205-680YL operates at 6.5 MHz. This difference affects high-frequency performance. Applications operating near or above 6.5 MHz require verification that the lower resonant frequency does not degrade circuit performance.

Q: What packaging differences exist between these inductors?

A: Both the PM125S-680M and SRR1205-680YL use nonstandard package types with similar physical dimensions (PM125S: 12.60mm × 11.60mm × 5.40mm; SRR1205: 12.70mm × 12.70mm × 5.50mm). Verify PCB layout compatibility before implementation.

Q: Does the SRR1205-680YL offer compliance advantages?

A: Yes. The SRR1205-680YL is RoHS3 compliant, while the PM125S-680M is non-compliant. For applications subject to RoHS regulations, the SRR1205-680YL provides regulatory compliance. Both parts are REACH unaffected and classified as EAR99.

Q: What is the inductance tolerance difference?

A: The PM125S-680M has ±20% tolerance, while the SRR1205-680YL has ±15% tolerance. The tighter tolerance of the substitute part provides improved inductance accuracy for precision circuit applications.