PM43-1R8M Equivalent & Substitute Parts

Part Overview

The PM43-1R8M is a 1.8 µH unshielded drum core wirewound inductor manufactured by Bourns Inc., rated for 1.95 A with a DC resistance of 64mOhm. This component is classified as obsolete, making identification of suitable substitute parts essential for ongoing design support and procurement continuity. The part operates across a temperature range of -40°C to 100°C and is not RoHS compliant.

Substiute Parts

PM43-1R8M

Bourns Inc.In Stock: 936PM43-1R8M Datasheet

Current PartRFQ

SDR0403-1R8ML

Bourns Inc.In Stock: 10386SDR0403-1R8ML Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the PM43-1R8M is determined by the following critical parameters:

• Inductance Value: Must match 1.8 µH with ±20% tolerance
• Current Rating: Substitute must support minimum 1.95 A; higher ratings are acceptable
• DC Resistance: Lower DCR values improve efficiency; 64mOhm is the baseline
• Core Material & Shielding: Ferrite, unshielded construction must be maintained
• Package Dimensions: Physical footprint of 4.50mm x 4.00mm x 4.60mm must be preserved for PCB compatibility
• Mounting Type: Surface mount configuration is required
• Operating Temperature Range: Minimum -40°C to 100°C; extended ranges are acceptable

The SDR0403-1R8ML qualifies as a direct substitute based on matching inductance, core type, shielding, package dimensions, and mounting configuration while providing superior electrical performance through higher current rating and lower DCR.

Parameter Comparison

Engineering Selection Recommendations

The SDR0403-1R8ML is the qualified substitute for the obsolete PM43-1R8M based on the following factors:

• Electrical Compatibility: Identical inductance value and tolerance ensure functional equivalence in circuit operation
• Physical Compatibility: Matching package dimensions and surface mount configuration enable direct PCB placement without layout modifications
• Performance Enhancement: The SDR0403-1R8ML provides 49% higher current rating (2.91 A vs. 1.95 A) and 34% lower maximum DC resistance (42mOhm vs. 64mOhm), resulting in improved thermal performance and reduced power dissipation
• Extended Operating Range: The substitute supports -40°C to 125°C, exceeding the original -40°C to 100°C specification
• Regulatory Compliance: The SDR0403-1R8ML is ROHS3 compliant and active in production, addressing obsolescence and regulatory requirements
• Availability: 10,300 units in stock versus 830 units for the original part

Frequently Asked Questions (FAQ)

Q: Can the SDR0403-1R8ML be used as a direct replacement for PM43-1R8M without circuit modifications?

A: Yes. Both parts share identical inductance values, tolerances, core materials, shielding configurations, and package dimensions. The substitute can be placed directly on existing PCBs designed for the PM43-1R8M.

Q: What are the advantages of using SDR0403-1R8ML over PM43-1R8M?

A: The SDR0403-1R8ML offers higher current rating (2.91 A vs. 1.95 A), lower DC resistance (42mOhm max vs. 64mOhm), extended operating temperature range (-40°C to 125°C vs. -40°C to 100°C), ROHS3 compliance, and active production status with superior inventory availability.

Q: Are there any electrical performance differences between these parts?

A: Both parts maintain the same inductance and tolerance specifications. The SDR0403-1R8ML exhibits lower DC resistance, which reduces I²R losses and improves efficiency. Self-resonant frequencies are comparable (90MHz vs. 92MHz).

Q: Does the substitute part fit the same PCB footprint?

A: Yes. Both parts have identical package dimensions of 4.50mm x 4.00mm x 4.60mm and use surface mount configuration, ensuring mechanical and electrical compatibility without PCB redesign.

Q: What is the impact of the lower DC resistance on circuit performance?

A: Lower DC resistance reduces power dissipation in the inductor, resulting in lower operating temperatures and improved circuit efficiency. This is a beneficial characteristic for thermal management.

Q: Is RoHS compliance a critical factor for this substitution?

A: The SDR0403-1R8ML is ROHS3 compliant while the PM43-1R8M is not. For applications subject to RoHS regulations or customer requirements, the substitute provides regulatory alignment. For legacy systems without RoHS mandates, both parts are functionally equivalent.