PM40-1R2K Equivalent & Substitute Parts

Part Overview

The PM40-1R2K is a 1.2 µH unshielded molded inductor manufactured by Bourns Inc., rated for 430 mA with a maximum DC resistance of 550 mOhm in a 1812 (4532 Metric) surface mount package. This part is classified as obsolete, making equivalent and substitute components necessary for ongoing design support and production continuity. Substitute parts must maintain electrical performance within the specified operating parameters while meeting current manufacturing and compliance standards.

Key Parameters

Parameter	Value
Inductance	1.2 µH
Tolerance	±10%
Current Rating	430 mA
DC Resistance (DCR)	550 mOhm Max
Package / Case	1812 (4532 Metric)
Mounting Type	Surface Mount
Operating Temperature	-55°C ~ 125°C
Shielding	Unshielded

Substitute Part Grouping Explanation

Substitution for the PM40-1R2K is determined by strict electrical and mechanical compatibility. The following parameters must be matched or exceeded:

Inductance Value: 1.2 µH (core requirement)
Current Rating: Minimum 430 mA
DC Resistance: Maximum 550 mOhm
Package: 1812 (4532 Metric) surface mount
Shielding: Unshielded configuration
Operating Temperature Range: Must support -55°C to 125°C or equivalent operational envelope

Substitute parts are categorized as direct equivalents when all electrical parameters and package specifications align. Parts with different inductance values or current ratings are excluded from direct substitution.

Parameter Comparison

Part Number	Manufacturer	Inductance	Tolerance	Current Rating (mA)	DCR (mOhm Max)	Core Type	Operating Temp (°C)	Product Status	RoHS Status
PM40-1R2K	Bourns Inc.	1.2 µH	±10%	430	550	Iron Powder	-55 ~ 125	Obsolete	Non-compliant
CM453232-1R2JL	Bourns Inc.	1.2 µH	±5%	430	550	Ferrite	-40 ~ 125	Active	ROHS3 Compliant
CM453232-1R2KL	Bourns Inc.	1.2 µH	±10%	430	550	Ferrite	-40 ~ 125	Active	ROHS3 Compliant
PM1812-1R2J-RC	Bourns Inc.	1.2 µH	±5%	430	550	Ferrite	-40 ~ 100	Active	ROHS3 Compliant
1812-122J	API Delevan Inc.	1.2 µH	±5%	604	550	Ferrite	-55 ~ 125	Active	Non-compliant
744766012	Würth Elektronik	1.2 µH	±10%	430	550	Ferrite	-40 ~ 105	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalents (Preferred for Replacement)

CM453232-1R2KL and CM453232-1R2JL are direct electrical equivalents with identical inductance, current rating, and DC resistance specifications. Both are manufactured by Bourns Inc. in active production status with ROHS3 compliance. CM453232-1R2KL matches the original ±10% tolerance specification, while CM453232-1R2JL offers improved ±5% tolerance. Both support the required operating temperature range of -40°C to 125°C, which covers the original -55°C to 125°C specification above -40°C.

Alternative Equivalents (Cross-Manufacturer Options)

744766012 (Würth Elektronik) provides electrical equivalence with ±10% tolerance matching and active production status. Operating temperature range is -40°C to 105°C, which limits low-temperature operation to -40°C. ROHS3 compliance is confirmed.

PM1812-1R2J-RC (Bourns Inc.) is electrically equivalent with ±5% tolerance and ROHS3 compliance. Operating temperature maximum is 100°C, which restricts high-temperature operation compared to the original specification.

Conditional Substitutes (Application-Dependent)

1812-122J (API Delevan Inc.) maintains 1.2 µH inductance and 550 mOhm DCR but provides higher current rating (604 mA versus 430 mA). This part is suitable only for applications where the higher current capability does not introduce thermal or performance concerns. RoHS non-compliance status must be evaluated against design requirements.

Frequently Asked Questions (FAQ)

Q: Can CM453232-1R2KL directly replace PM40-1R2K?

A: Yes. Both parts specify 1.2 µH inductance, 430 mA current rating, 550 mOhm maximum DCR, and 1812 (4532 Metric) surface mount package. The substitute is in active production with ROHS3 compliance. Operating temperature range is -40°C to 125°C, which covers the original specification above -40°C.

Q: What is the difference between CM453232-1R2JL and CM453232-1R2KL?

A: Both are Bourns Inc. ferrite-core inductors with identical electrical performance. The primary difference is inductance tolerance: CM453232-1R2JL specifies ±5% tolerance, while CM453232-1R2KL specifies ±10% tolerance matching the original part. Selection depends on tolerance requirements for the application.

Q: Why is the operating temperature range different for substitute parts?

A: Substitute parts specify -40°C to 125°C or -40°C to 105°C operating ranges, which differ from the original -55°C to 125°C. Applications requiring operation below -40°C must evaluate alternative options or confirm that the lower temperature limit is acceptable for the intended use.

Q: Is 1812-122J a suitable substitute?

A: 1812-122J maintains inductance and DCR specifications but provides 604 mA current rating versus the original 430 mA. This part is suitable only if the higher current capability does not introduce unintended thermal or performance effects. RoHS non-compliance must be evaluated against design standards.

Q: What is the package compatibility for all substitute parts?

A: All substitute parts use the 1812 (4532 Metric) surface mount package with identical footprint dimensions (0.177" L x 0.126" W / 4.50mm x 3.20mm). Height variations range from 0.126" to 0.142" (3.20mm to 3.60mm), which must be confirmed against PCB clearance requirements.

Q: Are all substitute parts RoHS compliant?

A: CM453232-1R2JL, CM453232-1R2KL, PM1812-1R2J-RC, and 744766012 are ROHS3 compliant. The original PM40-1R2K and 1812-122J are RoHS non-compliant. Compliance requirements must be confirmed for the target application and market.

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