PM125SH-331M Equivalent & Substitute Parts

Part Overview

The PM125SH-331M is a 330 µH shielded drum core wirewound inductor manufactured by Bourns Inc., rated for 680 mA continuous current with a maximum DC resistance of 510 mOhm. This surface mount component operates across the temperature range of -30°C to 100°C and is classified as obsolete. Due to its obsolete status, equivalent and substitute parts from active product lines are necessary to maintain design continuity and ensure long-term component availability for new production and field replacements.

Key Parameters

Parameter	PM125SH-331M Value
Inductance	330 µH
Current Rating	680 mA
DC Resistance (DCR)	510 mOhm Max
Tolerance	±20%
Shielding	Shielded
Core Material	Ferrite
Mounting Type	Surface Mount
Operating Temperature	-30°C ~ 100°C
Size / Dimension	0.492" L x 0.492" W (12.50mm x 12.50mm)
Height - Seated (Max)	0.256" (6.50mm)
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution eligibility for the PM125SH-331M is determined by the following critical parameters:

Inductance Value: 330 µH (exact match required)
Current Rating: Minimum 680 mA (equal or greater acceptable)
DC Resistance: Maximum 510 mOhm (equal or lower acceptable)
Shielding: Shielded configuration (required for EMI performance)
Core Material: Ferrite drum core wirewound construction
Mounting Type: Surface mount, nonstandard package
Operating Temperature Range: Must support minimum -30°C to 100°C

Substitute parts are classified into two categories:

Direct Equivalents meet all electrical parameters and physical dimensions of the original part, enabling drop-in replacement without circuit redesign.

Similar Alternatives maintain the same inductance, shielding, and core construction but may vary in current rating, DC resistance, physical dimensions, or temperature range. These require circuit validation to confirm compatibility with application requirements.

Parameter Comparison

Part Number	Manufacturer	Inductance	Current Rating	DCR (Max)	Tolerance	Shielding	Size (L x W)	Height (Max)	Operating Temp	Product Status	RoHS Status
PM125SH-331M	Bourns Inc.	330 µH	680 mA	510 mOhm	±20%	Shielded	0.492" x 0.492" (12.50mm x 12.50mm)	0.256" (6.50mm)	-30°C ~ 100°C	Obsolete	RoHS non-compliant
SRR1260-331K	Bourns Inc.	330 µH	1.15 A	580 mOhm	±10%	Shielded	0.492" x 0.492" (12.50mm x 12.50mm)	0.256" (6.50mm)	-40°C ~ 125°C	Active	ROHS3 Compliant
SRR1206-331KL	Bourns Inc.	330 µH	600 mA	660 mOhm	±10%	Shielded	0.500" x 0.500" (12.70mm x 12.70mm)	0.256" (6.50mm)	-40°C ~ 125°C	Active	ROHS3 Compliant
SRR1208-331KL	Bourns Inc.	330 µH	850 mA	650 mOhm	±10%	Shielded	0.500" x 0.500" (12.70mm x 12.70mm)	0.335" (8.50mm)	-40°C ~ 125°C	Active	ROHS3 Compliant
SRR1205-331KL	Bourns Inc.	330 µH	540 mA	1.34 Ohm	±10%	Shielded	0.500" x 0.500" (12.70mm x 12.70mm)	0.217" (5.50mm)	-40°C ~ 125°C	Active	ROHS3 Compliant
744771233	Würth Elektronik	330 µH	780 mA	510 mOhm	±20%	Shielded	0.472" x 0.472" (12.00mm x 12.00mm)	0.236" (6.00mm)	-40°C ~ 125°C	Active	ROHS3 Compliant
B82477G2334M000	EPCOS - TDK Electronics	330 µH	680 mA	510 mOhm	±20%	Shielded	0.484" x 0.484" (12.30mm x 12.30mm)	0.236" (6.00mm)	-55°C ~ 125°C	Active	ROHS3 Compliant
CDRH125NP-331MC	Sumida America Components Inc.	330 µH	680 mA	510 mOhm	±20%	Shielded	0.472" x 0.472" (12.00mm x 12.00mm)	0.236" (6.00mm)	-40°C ~ 100°C	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: SRR1260-331K

The SRR1260-331K from Bourns Inc. is the preferred direct equivalent. It maintains identical physical dimensions (0.492" x 0.492" x 0.256"), matching inductance of 330 µH, and equivalent DC resistance of 580 mOhm. The current rating of 1.15 A exceeds the original 680 mA requirement, providing design margin. This part is active in production, ROHS3 compliant, and operates across an extended temperature range of -40°C to 125°C, surpassing the original -30°C to 100°C specification.

Alternative Equivalent: B82477G2334M000

The B82477G2334M000 from EPCOS - TDK Electronics provides an exact electrical match with 330 µH inductance, 680 mA current rating, and 510 mOhm DC resistance. Physical dimensions are comparable (0.484" x 0.484" x 0.236"), and the part is ROHS3 compliant with active production status. The extended operating temperature range of -55°C to 125°C provides additional thermal margin.

Alternative Equivalent: CDRH125NP-331MC

The CDRH125NP-331MC from Sumida America Components Inc. matches all critical electrical parameters: 330 µH inductance, 680 mA current rating, and 510 mOhm DC resistance. Physical dimensions are compact (0.472" x 0.472" x 0.236"), and the part is ROHS3 compliant with active production status. Operating temperature range is -40°C to 100°C.

Secondary Alternative: 744771233

The 744771233 from Würth Elektronik (WE-PD series) provides 330 µH inductance with 780 mA current rating and 510 mOhm DC resistance, matching the original DC resistance specification. Physical dimensions are slightly smaller (0.472" x 0.472" x 0.236"), and the part carries AEC-Q200 automotive qualification. ROHS3 compliant with active production status and -40°C to 125°C operating range.

Conditional Alternatives: SRR1206-331KL and SRR1208-331KL

Both SRR1206-331KL and SRR1208-331KL maintain 330 µH inductance and shielded ferrite construction. The SRR1206-331KL provides 600 mA current rating with 660 mOhm DCR, while the SRR1208-331KL offers 850 mA current rating with 650 mOhm DCR. Both are ROHS3 compliant and active. Physical dimensions differ slightly (0.500" x 0.500"), and height varies (0.256" and 0.335" respectively). These parts are suitable only if circuit design accommodates the increased DCR and physical footprint changes.

Not Recommended: SRR1205-331KL

The SRR1205-331KL exhibits significantly elevated DC resistance of 1.34 Ohm, exceeding the original 510 mOhm specification by more than 2.6 times. Current rating of 540 mA falls below the original 680 mA requirement. This part is unsuitable for direct substitution.

Frequently Asked Questions (FAQ)

Q: Can SRR1260-331K be used as a direct replacement for PM125SH-331M?

A: Yes. The SRR1260-331K maintains identical physical dimensions, inductance value of 330 µH, and equivalent DC resistance. The higher current rating of 1.15 A provides additional design margin. The part is ROHS3 compliant and active in production.

Q: What is the impact of using a substitute part with higher DC resistance?

A: DC resistance directly affects power dissipation and voltage drop across the inductor. Parts with DCR exceeding 510 mOhm will generate additional heat and reduce circuit efficiency. Verify that thermal management and circuit performance remain acceptable within application requirements.

Q: Are all substitute parts ROHS3 compliant?

A: All recommended substitute parts (SRR1260-331K, B82477G2334M000, CDRH125NP-331MC, and 744771233) are ROHS3 compliant. The original PM125SH-331M is RoHS non-compliant. Compliance verification is required for applications subject to RoHS regulations.

Q: Do physical dimension differences affect PCB layout?

A: Yes. While most substitutes maintain the 12.5mm footprint, some alternatives (SRR1206-331KL, SRR1208-331KL) use 12.7mm dimensions, and others (744771233, CDRH125NP-331MC) use 12.0mm dimensions. Height variations range from 5.5mm to 8.5mm. PCB layout validation is required for parts with dimension changes.

Q: Which substitute offers the best thermal performance?

A: The B82477G2334M000 provides the widest operating temperature range (-55°C to 125°C) and matches the original electrical specifications exactly. The SRR1260-331K offers extended range (-40°C to 125°C) with higher current capacity.

Q: Can SRR1205-331KL be used as a substitute?

A: No. The SRR1205-331KL exhibits 1.34 Ohm DC resistance, which exceeds the original 510 mOhm specification by 2.6 times, and its 540 mA current rating falls below the required 680 mA. This part is not suitable for direct substitution.

Q: What certifications does the 744771233 carry?

A: The 744771233 carries AEC-Q200 automotive qualification in addition to ROHS3 compliance. This part is suitable for automotive and high-reliability applications.

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