PM43-6R8M Equivalent & Substitute Parts Reference

Part Overview

The PM43-6R8M is a 6.8 µH unshielded drum core wirewound inductor manufactured by Bourns Inc., rated for 950 mA with a DC resistance of 132mOhm. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. The part operates across a temperature range of -40°C to 100°C and is packaged in a nonstandard surface mount configuration measuring 4.50mm × 4.00mm × 4.60mm (max height).

Key Parameters

Parameter	Value
Inductance	6.8 µH
Tolerance	±20%
Current Rating	950 mA
DC Resistance (DCR)	132mOhm
Core Material	Ferrite
Shielding	Unshielded
Mounting Type	Surface Mount
Operating Temperature	-40°C ~ 100°C
Package Dimensions	4.50mm L × 4.00mm W × 4.60mm H (max)
Self Resonant Frequency	41 MHz

Substitute Part Grouping Explanation

Substitute parts for the PM43-6R8M are qualified based on the following critical parameters:

Inductance Value: 6.8 µH (exact match required)
Inductance Tolerance: ±20% (matching specification)
Core Type: Ferrite, unshielded drum core wirewound construction
Mounting: Surface mount, nonstandard package
DC Resistance: Within acceptable range for circuit performance (120–132mOhm)
Current Rating: Minimum 950 mA (equal or higher acceptable)
Operating Temperature Range: Minimum -40°C to 100°C coverage
Package Footprint: Compatible with 4.50mm × 4.00mm × 4.60mm (max height) placement

Two substitute parts meet these criteria: the SDR0403-6R8ML (direct manufacturer equivalent from Bourns Inc.) and the CR43NP-6R8MC (cross-manufacturer alternative from Sumida America Components Inc.).

Parameter Comparison

Parameter	PM43-6R8M (Main)	SDR0403-6R8ML (Direct)	CR43NP-6R8MC (Cross)
Manufacturer	Bourns Inc.	Bourns Inc.	Sumida America Components Inc.
Inductance	6.8 µH	6.8 µH	6.8 µH
Tolerance	±20%	±20%	±20%
Current Rating	950 mA	1.41 A	950 mA
DC Resistance (DCR)	132mOhm	120mOhm Max	131.2mOhm Max
Core Material	Ferrite	Ferrite	Ferrite
Shielding	Unshielded	Unshielded	Unshielded
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Operating Temperature	-40°C ~ 100°C	-40°C ~ 125°C	-40°C ~ 100°C
Self Resonant Frequency	41 MHz	40 MHz	42.3 MHz
Product Status	Obsolete	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging	Nonstandard	Tape & Reel (TR)	Tape & Reel (TR)

Engineering Selection Recommendations

SDR0403-6R8ML is the primary substitute option. As a direct Bourns Inc. manufacturer equivalent with active product status, it provides the highest compatibility assurance. The SDR0403-6R8ML offers improved specifications including higher current rating (1.41 A vs. 950 mA), lower DC resistance (120mOhm Max vs. 132mOhm), and extended operating temperature range (-40°C to 125°C vs. -40°C to 100°C). ROHS3 compliance addresses regulatory requirements where the original PM43-6R8M does not. Inductance, tolerance, core material, and shielding characteristics remain identical.

CR43NP-6R8MC serves as a secondary cross-manufacturer substitute from Sumida America Components Inc. This part maintains electrical equivalence with matching inductance, tolerance, current rating, and DC resistance specifications. Operating temperature range and self-resonant frequency remain within acceptable parameters. ROHS3 compliance is provided. Physical dimensions differ slightly (4.80mm L × 4.30mm W vs. 4.50mm × 4.00mm), requiring PCB layout verification before implementation.

Both substitutes are available in active production with established inventory levels, ensuring procurement reliability compared to the obsolete PM43-6R8M.

Frequently Asked Questions (FAQ)

Q: Can the SDR0403-6R8ML directly replace the PM43-6R8M without circuit modification?

A: Yes. The SDR0403-6R8ML maintains identical inductance (6.8 µH), tolerance (±20%), core material (ferrite), shielding (unshielded), and mounting type (surface mount). The higher current rating and lower DC resistance represent performance improvements compatible with the original design intent.

Q: What is the primary advantage of using SDR0403-6R8ML over CR43NP-6R8MC?

A: The SDR0403-6R8ML is manufactured by Bourns Inc., the original PM43-6R8M manufacturer, providing design continuity and established qualification history. It also offers superior electrical performance with higher current capacity (1.41 A vs. 950 mA) and lower DC resistance (120mOhm Max vs. 131.2mOhm Max).

Q: Are there physical placement differences between these substitutes?

A: The SDR0403-6R8ML maintains identical footprint dimensions (4.50mm × 4.00mm × 4.60mm max height) as the PM43-6R8M. The CR43NP-6R8MC has slightly larger length and width (4.80mm × 4.30mm) but identical height, requiring PCB layout verification for tight spacing applications.

Q: Do both substitutes meet RoHS compliance requirements?

A: Yes. Both SDR0403-6R8ML and CR43NP-6R8MC are ROHS3 compliant, whereas the original PM43-6R8M is RoHS non-compliant. This addresses regulatory requirements for new designs and procurement cycles.

Q: What is the impact of the different self-resonant frequencies?

A: The self-resonant frequencies (SDR0403-6R8ML: 40 MHz, CR43NP-6R8MC: 42.3 MHz, PM43-6R8M: 41 MHz) are all within a narrow range suitable for the same circuit applications. Selection should be based on specific high-frequency performance requirements in your design.

Q: Can I use CR43NP-6R8MC if SDR0403-6R8ML is unavailable?

A: Yes. The CR43NP-6R8MC provides electrical equivalence with matching inductance, tolerance, current rating, and DC resistance. Verify PCB layout compatibility due to slightly larger physical dimensions before implementation.

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