PM40-4R7K Equivalent & Substitute Parts

Part Overview

The PM40-4R7K is a 4.7 µH unshielded molded inductor manufactured by Bourns Inc., rated for 315 mA with a maximum DC resistance of 1 Ohm in a 1812 (4532 Metric) surface mount package. This part is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain electrical and mechanical compatibility for ongoing production and repair applications.

Key Parameters

Parameter	Value
Inductance	4.7 µH
Current Rating	315 mA
DC Resistance (DCR)	1 Ohm Max
Tolerance	±10%
Package / Case	1812 (4532 Metric)
Mounting Type	Surface Mount
Operating Temperature Range	-55°C ~ 125°C
Shielding	Unshielded
Q @ Frequency	50 @ 7.96 MHz
Self Resonant Frequency	35 MHz

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Inductance: 4.7 µH (exact match required)
Current Rating: 315 mA minimum
DC Resistance: 1 Ohm maximum
Package: 1812 (4532 Metric) surface mount
Tolerance: ±10% or tighter
Shielding: Unshielded

Secondary Compatibility Factors:

Operating temperature range must encompass or match the original specification
Q factor and self-resonant frequency must remain within acceptable ranges for the application
Mounting type must be surface mount

Substitute parts are classified into two categories:

Direct Substitutes (Electrical & Mechanical Equivalence): Parts meeting all primary criteria with identical or superior electrical performance and active product status.

Similar Substitutes (Functional Equivalence with Parameter Variations): Parts meeting core electrical requirements but with variations in core material, temperature range, or other secondary parameters that may require application-level verification.

Parameter Comparison

Part Number	Manufacturer	Inductance	Current Rating (mA)	DCR (Ohm Max)	Tolerance	Core Type	Operating Temp (°C)	Product Status	RoHS Status
PM40-4R7K	Bourns Inc.	4.7 µH	315	1	±10%	Iron Powder	-55 ~ 125	Obsolete	Non-compliant
CM453232-4R7JL	Bourns Inc.	4.7 µH	315	1	±5%	Ferrite	-40 ~ 125	Active	ROHS3 Compliant
CM453232-4R7KL	Bourns Inc.	4.7 µH	315	1	±10%	Ferrite	-40 ~ 125	Active	ROHS3 Compliant
1812-472J	API Delevan Inc.	4.7 µH	448	1	±5%	Ferrite	-55 ~ 125	Active	Non-compliant
3613C4R7K	TE Connectivity Passive Product	4.7 µH	315	1	±10%	Ferrite	-30 ~ 100	Active	ROHS3 Compliant
74476604	Würth Elektronik	4.7 µH	315	1	±10%	Ferrite	-40 ~ 105	Active	ROHS3 Compliant
IMC1812BN4R7K	Vishay Dale	4.7 µH	315	1	±10%	Iron Powder	-55 ~ 125	Active	Non-compliant
IMC1812ER4R7K	Vishay Dale	4.7 µH	315	1	±10%	Iron Powder	-55 ~ 125	Active	ROHS3 Compliant
IMC1812RQ4R7K	Vishay Dale	4.7 µH	315	1	±10%	Iron Powder	-55 ~ 125	Active	Non-compliant

Engineering Selection Recommendations

Preferred Direct Substitutes (Active Status, Full Compatibility):

CM453232-4R7KL (Bourns Inc.) is the primary recommended substitute. It maintains identical electrical specifications to the PM40-4R7K with ±10% tolerance, 315 mA current rating, and 1 Ohm maximum DCR. The part is active with ROHS3 compliance and ferrite core construction. Operating temperature range is -40°C to 125°C, which covers the original -55°C lower limit with a 15°C reduction. Inventory availability is 25,200 units.

IMC1812ER4R7K (Vishay Dale) provides an alternative with identical electrical parameters and full temperature range coverage (-55°C to 125°C). This part features iron powder core construction matching the original PM40-4R7K core material, active product status, and ROHS3 compliance. Inventory is 5,196 units.

Secondary Substitutes (Active Status, Parameter Variations):

CM453232-4R7JL (Bourns Inc.) offers tighter tolerance (±5%) with identical current rating and DCR. Operating temperature is -40°C to 125°C. ROHS3 compliant with 4,018 units in stock.

74476604 (Würth Elektronik) maintains all electrical specifications with ferrite core, ROHS3 compliance, and 6,400 units available. Operating temperature range is -40°C to 105°C, providing 20°C reduction at the upper limit.

IMC1812BN4R7K (Vishay Dale) matches the original iron powder core material with full temperature range (-55°C to 125°C) and active status. RoHS non-compliance and 839 units in stock.

Application-Specific Considerations:

For applications requiring full -55°C to 125°C temperature coverage, select IMC1812ER4R7K or IMC1812BN4R7K.

For RoHS3 compliance requirements, select CM453232-4R7KL, CM453232-4R7JL, 74476604, or IMC1812ER4R7K.

For iron powder core preference, select IMC1812ER4R7K (ROHS3 compliant, active) or IMC1812BN4R7K (non-compliant, active).

1812-472J (API Delevan Inc.) provides higher current rating (448 mA) with identical inductance and DCR. This part is suitable only for applications where the additional current margin is beneficial and the -55°C to 125°C temperature range is required. RoHS non-compliant.

3613C4R7K (TE Connectivity) is suitable for applications with operating temperature limits of -30°C to 100°C. ROHS3 compliant with 2,365 units in stock.

Frequently Asked Questions (FAQ)

Q: Can CM453232-4R7KL directly replace PM40-4R7K in all applications?

A: CM453232-4R7KL meets all primary electrical and mechanical specifications. The operating temperature range is -40°C to 125°C versus the original -55°C to 125°C. If your application operates above -40°C, this substitute is fully compatible. For applications requiring -55°C operation, select IMC1812ER4R7K or IMC1812BN4R7K.

Q: What is the difference between ferrite and iron powder core inductors?

A: Both core materials are provided in the specification data. Ferrite cores (CM453232 series, 74476604, 1812-472J, 3613C4R7K) and iron powder cores (PM40-4R7K, IMC1812 series) maintain identical inductance, current rating, and DCR values. Core material selection depends on application-specific requirements such as frequency response, EMI characteristics, and thermal performance.

Q: Does tolerance affect substitution compatibility?

A: The PM40-4R7K specifies ±10% tolerance. Substitutes with ±10% tolerance (CM453232-4R7KL, 3613C4R7K, 74476604, IMC1812 series) are directly compatible. Substitutes with tighter tolerance (±5%, such as CM453232-4R7JL and 1812-472J) provide improved accuracy and are also compatible.

Q: Is RoHS compliance required for my application?

A: RoHS compliance is determined by your end-use requirements and regional regulations. ROHS3-compliant substitutes include CM453232-4R7KL, CM453232-4R7JL, 74476604, and IMC1812ER4R7K. Non-compliant options include PM40-4R7K, 1812-472J, IMC1812BN4R7K, and IMC1812RQ4R7K.

Q: Can I use 1812-472J as a substitute despite its higher current rating?

A: 1812-472J meets the core electrical specifications (4.7 µH, 1 Ohm DCR) and package requirements. The 448 mA current rating exceeds the 315 mA requirement, providing additional margin. However, this part is RoHS non-compliant and has a -55°C to 125°C temperature range. Use this substitute only if RoHS compliance is not required and the higher current rating is acceptable for your circuit design.

Q: What packaging options are available?

A: All listed substitutes are supplied in 1812 (4532 Metric) surface mount package. Packaging formats vary: CM453232-4R7KL and CM453232-4R7JL are supplied in Tape & Reel (TR); 1812-472J, 3613C4R7K, 74476604, IMC1812ER4R7K, and IMC1812RQ4R7K are supplied in Tape & Reel (TR); IMC1812BN4R7K is supplied in Bulk.

Q: Which substitute offers the best inventory availability?

A: CM453232-4R7KL has the highest inventory with 25,200 units in stock, followed by 74476604 with 6,400 units and IMC1812ER4R7K with 5,196 units.

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