PM105S-271M Equivalent & Substitute Parts

Part Overview

The PM105S-271M is a 270 µH shielded drum core wirewound inductor manufactured by Bourns Inc., rated for 490 mA with a maximum DC resistance of 780mOhm. This surface mount component features ferrite core construction with ±20% inductance tolerance and operates across -30°C to 100°C. The part is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	PM105S-271M
Inductance	270 µH
Current Rating	490 mA
DC Resistance (Max)	780mOhm
Inductance Tolerance	±20%
Shielding	Shielded
Core Material	Ferrite
Mounting Type	Surface Mount
Operating Temperature	-30°C ~ 100°C
Self Resonant Frequency	5 MHz
RoHS Status	Non-compliant

Substitute Part Grouping Explanation

Substitution eligibility for the PM105S-271M is determined by the following critical parameters: inductance value (270 µH), core material (ferrite), mounting type (surface mount), and shielding configuration. All substitute parts must maintain the 270 µH inductance specification. Current rating, DC resistance, and operating temperature range are secondary selection criteria that determine application suitability based on circuit requirements.

The PM105S-271M has three qualified substitutes from Bourns Inc.:

Direct Substitute (Preferred): PM105SB-271K-RC maintains shielded construction and identical inductance with improved tolerance (±10%) and extended temperature range (-40°C ~ 125°C). This part is active and RoHS3 compliant.

Similar Substitutes: SDR1006-271KL and SRR0908-271YL both provide 270 µH inductance with higher current ratings (570 mA and 600 mA respectively) and active product status. SDR1006-271KL is unshielded, while SRR0908-271YL maintains shielded construction with different package configuration (8-SMD, Gull Wing).

Parameter Comparison

Parameter	PM105S-271M	PM105SB-271K-RC	SDR1006-271KL	SRR0908-271YL
Inductance	270 µH	270 µH	270 µH	270 µH
Current Rating (Amps)	490 mA	410 mA	570 mA	600 mA
DC Resistance (Max)	780mOhm	870mOhm	970mOhm	700mOhm
Inductance Tolerance	±20%	±10%	±10%	±15%
Shielding	Shielded	Shielded	Unshielded	Shielded
Core Material	Ferrite	Ferrite	Ferrite	Ferrite
Operating Temperature	-30°C ~ 100°C	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C
Self Resonant Frequency	5 MHz	5 MHz	4.6 MHz	3.4 MHz
Product Status	Obsolete	Active	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

PM105SB-271K-RC is the primary substitute for new designs. It maintains shielded construction identical to the original part, offers improved inductance tolerance (±10% vs ±20%), and is RoHS3 compliant with active product status. The extended operating temperature range (-40°C ~ 125°C) provides greater design margin. Current rating of 410 mA is lower than the original 490 mA; select this part only if circuit current requirements do not exceed 410 mA.

SRR0908-271YL is suitable for applications requiring higher current capacity (600 mA) with maintained shielding and RoHS3 compliance. The package configuration differs (8-SMD, Gull Wing vs nonstandard), requiring PCB layout verification. Self resonant frequency is lower (3.4 MHz vs 5 MHz).

SDR1006-271KL provides the highest current rating (570 mA) and lowest DC resistance (970mOhm max) among substitutes. Unshielded construction makes this part suitable only for applications where electromagnetic shielding is not required. RoHS3 compliant with active status.

All substitutes are RoHS3 compliant and have unlimited moisture sensitivity level (MSL 1), improving supply chain reliability compared to the obsolete original part.

Frequently Asked Questions (FAQ)

Q: Can PM105SB-271K-RC directly replace PM105S-271M in existing designs?

A: PM105SB-271K-RC maintains the same 270 µH inductance, shielded construction, and surface mount configuration. However, the current rating is 410 mA versus 490 mA in the original. Substitution is valid only if circuit current requirements do not exceed 410 mA. Verify DC resistance impact (870mOhm vs 780mOhm) on circuit performance.

Q: What is the difference between shielded and unshielded substitutes?

A: PM105S-271M, PM105SB-271K-RC, and SRR0908-271YL are shielded inductors, reducing electromagnetic interference. SDR1006-271KL is unshielded and suitable only for applications where EMI shielding is not required. Shielding affects board layout and component spacing requirements.

Q: Are all substitutes RoHS3 compliant?

A: Yes. PM105SB-271K-RC, SDR1006-271KL, and SRR0908-271YL are all RoHS3 compliant. The original PM105S-271M is RoHS non-compliant, making these substitutes necessary for designs requiring regulatory compliance.

Q: How do package differences affect PCB design?

A: PM105S-271M, PM105SB-271K-RC, and SDR1006-271KL use nonstandard surface mount packages with similar footprints (approximately 10mm x 9mm). SRR0908-271YL uses 8-SMD, Gull Wing package with different pin configuration and height (7.80mm vs 4.80-5.50mm), requiring PCB layout modification.

Q: Which substitute has the lowest DC resistance?

A: SRR0908-271YL has the lowest maximum DC resistance at 700mOhm, compared to 780mOhm for the original part. This reduces power dissipation in high-current applications.

Q: What is the impact of inductance tolerance differences?

A: PM105S-271M has ±20% tolerance. PM105SB-271K-RC and SDR1006-271KL offer tighter ±10% tolerance, improving circuit performance consistency. SRR0908-271YL provides ±15% tolerance. Tighter tolerance reduces design margin requirements.

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