PM42S-8R2 Equivalent & Substitute Parts Reference

Part Overview

The PM42S-8R2 is an 8.2 µH shielded drum core wirewound inductor manufactured by Bourns Inc., rated for 680 mA continuous current with a maximum DC resistance of 245 mOhm. This component is classified as obsolete product status. Due to its obsolescence, equivalent substitute parts from active product lines are necessary to maintain design continuity and ensure long-term component availability for new production runs and field replacements.

Key Parameters

Parameter	Value
Inductance	8.2 µH
Inductance Tolerance	±30%
Current Rating	680 mA
DC Resistance (DCR)	245 mOhm Max
Core Material	Ferrite
Shielding	Shielded
Mounting Type	Surface Mount
Physical Dimensions	0.189" L x 0.189" W (4.80mm x 4.80mm)
Height - Seated (Max)	0.079" (2.00mm)
Operating Temperature Range	-30°C ~ 100°C
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitute parts for the PM42S-8R2 are qualified based on the following critical parameters:

Inductance Value: Must be 8.2 µH with ±30% tolerance
Core Type & Shielding: Ferrite core with shielding required
Mounting Configuration: Surface mount technology
Physical Footprint: 4.80mm x 4.80mm base dimensions to ensure PCB layout compatibility
Current Handling Capability: Rated current must meet or exceed the 680 mA requirement
DC Resistance: Lower DCR values indicate improved efficiency and reduced power dissipation

The substitute parts SRR4018-8R2Y and SRR4011-8R2YL both meet the core electrical and mechanical compatibility criteria. Both are active products from Bourns Inc. with enhanced specifications compared to the obsolete PM42S-8R2.

Parameter Comparison

Parameter	PM42S-8R2 (Main)	SRR4018-8R2Y (Direct)	SRR4011-8R2YL (Similar)
Inductance	8.2 µH	8.2 µH	8.2 µH
Inductance Tolerance	±30%	±30%	±30%
Current Rating (Amps)	680 mA	1.4 A	1.1 A
DC Resistance (DCR)	245 mOhm Max	135 mOhm Max	215 mOhm Max
Core Material	Ferrite	Ferrite	Ferrite
Shielding	Shielded	Shielded	Shielded
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Physical Dimensions	0.189" L x 0.189" W (4.80mm x 4.80mm)	0.189" L x 0.189" W (4.80mm x 4.80mm)	0.189" L x 0.189" W (4.80mm x 4.80mm)
Height - Seated (Max)	0.079" (2.00mm)	0.079" (2.00mm)	0.051" (1.30mm)
Operating Temperature Range	-30°C ~ 100°C	-40°C ~ 125°C	-40°C ~ 125°C
Product Status	Obsolete	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

SRR4018-8R2Y (Direct Substitute - Recommended)

The SRR4018-8R2Y is the primary substitute for the obsolete PM42S-8R2. This part maintains identical inductance and footprint specifications while providing superior electrical performance. The current rating of 1.4 A exceeds the original 680 mA requirement, and the DC resistance of 135 mOhm is significantly lower than the 245 mOhm maximum of the PM42S-8R2, resulting in reduced power dissipation. The SRR4018-8R2Y is ROHS3 compliant and carries active product status, ensuring long-term availability. The extended operating temperature range of -40°C ~ 125°C provides greater thermal margin compared to the original -30°C ~ 100°C specification.

SRR4011-8R2YL (Alternative Substitute)

The SRR4011-8R2YL serves as an alternative substitute when SRR4018-8R2Y availability is constrained. This part meets all core electrical requirements with a 1.1 A current rating and 215 mOhm maximum DC resistance. The primary distinction is the reduced seated height of 0.051" (1.30mm) compared to 0.079" (2.00mm) for both the original and direct substitute. This lower profile may provide advantages in space-constrained PCB layouts. The SRR4011-8R2YL is also ROHS3 compliant with active product status.

Both substitute parts are manufactured by Bourns Inc., ensuring consistency in design philosophy and quality standards. Selection between these two options should be based on PCB height constraints and current margin requirements for the specific application.

Frequently Asked Questions (FAQ)

Q: Can the SRR4018-8R2Y directly replace the PM42S-8R2 without PCB modifications?

A: Yes. Both parts share identical inductance values, footprint dimensions (4.80mm x 4.80mm), and seated height (0.079" / 2.00mm). No PCB layout changes are required for this substitution.

Q: What is the primary advantage of using SRR4018-8R2Y over the original PM42S-8R2?

A: The SRR4018-8R2Y provides lower DC resistance (135 mOhm vs. 245 mOhm), higher current rating (1.4 A vs. 680 mA), extended temperature range (-40°C ~ 125°C vs. -30°C ~ 100°C), and ROHS3 compliance. These improvements reduce power dissipation and ensure regulatory compliance.

Q: When should SRR4011-8R2YL be selected instead of SRR4018-8R2Y?

A: The SRR4011-8R2YL should be selected when PCB height is constrained. Its seated height of 0.051" (1.30mm) is 0.028" lower than the SRR4018-8R2Y. Both parts meet the 680 mA current requirement of the original design.

Q: Are there any electrical performance differences between the two substitute parts?

A: Yes. The SRR4018-8R2Y has lower DC resistance (135 mOhm vs. 215 mOhm) and higher current rating (1.4 A vs. 1.1 A). For applications where power dissipation is critical, SRR4018-8R2Y is the superior choice. For current-limited applications, both parts are acceptable.

Q: What is the packaging format for these substitute parts?

A: Both SRR4018-8R2Y and SRR4011-8R2YL are supplied in Tape & Reel (TR) format, standard for high-volume surface mount production.

Q: Are both substitute parts RoHS compliant?

A: Yes. Both SRR4018-8R2Y and SRR4011-8R2YL are ROHS3 compliant. The original PM42S-8R2 is RoHS non-compliant, making substitution necessary for designs requiring regulatory compliance.

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