PM43-1R4M Equivalent & Substitute Parts

Part Overview

The PM43-1R4M is a 1.4 µH unshielded drum core wirewound inductor manufactured by Bourns Inc., rated for 2.52 A with 57mOhm DC resistance. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The part operates across -40°C to 100°C and is housed in a nonstandard surface mount package measuring 4.50mm × 4.00mm × 4.60mm (max height).

Key Parameters

Parameter	Value
Inductance	1.4 µH
Inductance Tolerance	±20%
Current Rating	2.52 A
DC Resistance (DCR)	57mOhm
Core Material	Ferrite
Shielding	Unshielded
Operating Temperature Range	-40°C ~ 100°C
Mounting Type	Surface Mount
Package Dimensions	4.50mm L × 4.00mm W × 4.60mm H (max)
Self Resonant Frequency	101 MHz
Inductance Test Frequency	7.96 MHz
RoHS Status	RoHS non-compliant
MSL Rating	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the PM43-1R4M are qualified based on the following critical parameters:

Inductance Value: 1.4 µH (±20% tolerance maintained across all substitutes)
Core Material: Ferrite unshielded construction
Shielding Type: Unshielded
Package Dimensions: 4.50mm × 4.00mm footprint with 4.60mm maximum seated height
Mounting Type: Surface mount
Inductance Test Frequency: 7.96 MHz or equivalent measurement standard

Substitutes are classified into two categories:

Direct Substitute (Active Status): SDR0403-1R4ML meets all critical electrical and mechanical parameters with enhanced current rating and improved DC resistance, offering superior performance characteristics while maintaining dimensional compatibility.

Similar Substitute (Active Status): CD43NP-1R4MC provides equivalent inductance and core material with comparable current rating and DC resistance specifications, maintaining full dimensional and thermal compatibility.

Parameter Comparison

Parameter	PM43-1R4M (Main)	SDR0403-1R4ML (Direct)	CD43NP-1R4MC (Similar)
Manufacturer	Bourns Inc.	Bourns Inc.	Sumida America Components Inc.
Inductance	1.4 µH	1.4 µH	1.4 µH
Inductance Tolerance	±20%	±20%	±20%
Current Rating (Amps)	2.52 A	3.3 A	2.5 A
DC Resistance (DCR)	57mOhm	38mOhm Max	56.2mOhm Max
Core Material	Ferrite	Ferrite	Ferrite
Shielding	Unshielded	Unshielded	Unshielded
Operating Temperature Range	-40°C ~ 100°C	-40°C ~ 125°C	-40°C ~ 100°C
Package Dimensions	4.50mm × 4.00mm × 4.60mm	4.50mm × 4.00mm × 4.60mm	4.50mm × 4.00mm × 4.60mm
Self Resonant Frequency	101 MHz	110 MHz	Not specified
Inductance Test Frequency	7.96 MHz	1 kHz	7.96 MHz
Product Status	Obsolete	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging	Not specified	Tape & Reel (TR)	Tape & Reel (TR)

Engineering Selection Recommendations

SDR0403-1R4ML is the primary substitute for PM43-1R4M applications. This Bourns Inc. component maintains identical inductance and package dimensions while providing superior electrical performance through reduced DC resistance (38mOhm max versus 57mOhm) and higher current rating (3.3 A versus 2.52 A). The extended operating temperature range (-40°C to 125°C) and ROHS3 compliance address regulatory requirements absent in the obsolete PM43-1R4M. Active product status ensures long-term availability and supply chain stability.

CD43NP-1R4MC serves as an alternative substitute when SDR0403-1R4ML is unavailable. Manufactured by Sumida America Components Inc., this component delivers equivalent inductance and core material specifications with current rating (2.5 A) and DC resistance (56.2mOhm max) closely matching the original PM43-1R4M. ROHS3 compliance and active product status provide regulatory alignment and supply continuity. Operating temperature range matches the original specification (-40°C to 100°C).

Both substitutes maintain full dimensional and mechanical compatibility with PM43-1R4M footprints and mounting requirements.

Frequently Asked Questions (FAQ)

Q: Can SDR0403-1R4ML directly replace PM43-1R4M in existing designs?

A: Yes. SDR0403-1R4ML maintains identical inductance value (1.4 µH ±20%), core material (ferrite unshielded), and package dimensions (4.50mm × 4.00mm × 4.60mm max height). The improved DC resistance and current rating provide enhanced performance without circuit modification.

Q: What is the primary difference between the two substitute options?

A: SDR0403-1R4ML offers superior electrical performance with lower DC resistance (38mOhm max) and higher current rating (3.3 A), plus extended temperature range (-40°C to 125°C). CD43NP-1R4MC provides closer electrical matching to the original PM43-1R4M specifications while maintaining ROHS3 compliance and active availability.

Q: Are both substitutes available in Tape & Reel packaging?

A: Yes. Both SDR0403-1R4ML and CD43NP-1R4MC are supplied in Tape & Reel (TR) packaging, suitable for automated assembly processes.

Q: Does the inductance test frequency difference affect substitution validity?

A: SDR0403-1R4ML is tested at 1 kHz while PM43-1R4M and CD43NP-1R4MC are tested at 7.96 MHz. Both measurement standards fall within acceptable inductor characterization practices. The ±20% inductance tolerance specification applies across both test frequencies, ensuring functional equivalence in circuit applications.

Q: Are there RoHS compliance considerations for substitution?

A: PM43-1R4M is RoHS non-compliant. Both substitutes (SDR0403-1R4ML and CD43NP-1R4MC) are ROHS3 compliant, meeting current regulatory requirements for new designs and production.

Q: What is the moisture sensitivity level for these components?

A: All three components carry MSL 1 (Unlimited) rating, indicating no moisture sensitivity restrictions for storage or handling.

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