PM3308-221M Equivalent & Substitute Parts

Part Overview

The PM3308-221M is a 220 µH unshielded drum core wirewound inductor manufactured by Bourns Inc., rated for 400 mA with a maximum DC resistance of 1.9Ohm. This component is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production support. The part operates across an industrial temperature range of -55°C to 125°C and is mounted as a surface mount device in a nonstandard package configuration.

Key Parameters

Parameter	Value
Inductance	220 µH
Current Rating	400 mA
DC Resistance (Max)	1.9Ohm
Tolerance	±20%
Shielding	Unshielded
Core Type	Drum Core, Ferrite
Mounting Type	Surface Mount
Operating Temperature	-55°C ~ 125°C
Inductance Test Frequency	100 kHz

Substitute Part Grouping Explanation

Substitution eligibility for the PM3308-221M is determined by strict alignment of electrical and mechanical parameters. The critical parameters governing substitution are:

Inductance value: 220 µH (exact match required)
Current rating: 400 mA (minimum requirement)
DC resistance: 1.9Ohm maximum (electrical performance constraint)
Tolerance: ±20% (specification match)
Shielding configuration: Unshielded (electromagnetic compatibility requirement)
Mounting type: Surface Mount (assembly compatibility)
Package dimensions: Nonstandard (physical fit requirement)

Two substitute parts meet these criteria with varying degrees of parameter alignment. The P0762.224NLT from Pulse Electronics provides a direct electrical equivalent with active product status. The AX97-20221 from Triad Magnetics offers improved DC resistance performance (1.3Ohm maximum) while maintaining all core electrical specifications.

Parameter Comparison

Parameter	PM3308-221M (Bourns)	P0762.224NLT (Pulse Electronics)	AX97-20221 (Triad Magnetics)
Inductance	220 µH	220 µH	220 µH
Current Rating	400 mA	400 mA	400 mA
Current - Saturation	500 mA	500 mA	Not specified
DC Resistance (Max)	1.9Ohm	1.9Ohm	1.3Ohm
Tolerance	±20%	±20%	±20%
Shielding	Unshielded	Unshielded	Unshielded
Core Type	Drum Core, Ferrite	Wirewound	Drum Core, Ferrite
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Operating Temperature	-55°C ~ 125°C	-40°C ~ 130°C	-40°C ~ 85°C
Inductance Test Frequency	100 kHz	100 kHz	100 kHz
Size / Dimension	0.512" L x 0.374" W (13.00mm x 9.50mm)	0.510" L x 0.370" W (12.95mm x 9.40mm)	0.530" L x 0.370" W (13.46mm x 9.40mm)
Height - Seated (Max)	0.118" (3.00mm)	0.118" (3.00mm)	0.138" (4.60mm)
Product Status	Obsolete	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For applications requiring PM3308-221M replacement, the P0762.224NLT from Pulse Electronics is the primary substitute. This part maintains identical electrical specifications (220 µH, 400 mA, 1.9Ohm maximum DC resistance) and is currently in active production status. The P0762.224NLT achieves ROHS3 compliance and provides superior long-term supply chain availability. Physical dimensions are within 0.002" tolerance across length and width, with matching seated height of 0.118".

The AX97-20221 from Triad Magnetics serves as an alternative substitute with enhanced electrical performance. The reduced DC resistance of 1.3Ohm maximum provides lower power dissipation compared to the original specification. This part is also ROHS3 compliant and actively produced. However, the operating temperature range is limited to -40°C to 85°C, which may not accommodate the original part's lower temperature extreme of -55°C. Additionally, the seated height of 0.138" exceeds the original by 0.020", requiring verification of PCB layout clearance.

Selection between substitutes depends on application-specific requirements: use P0762.224NLT for direct parameter matching and temperature range coverage; use AX97-20221 where reduced DC resistance and lower power dissipation provide design benefits and thermal environment constraints permit the narrower operating range.

Frequently Asked Questions (FAQ)

Q: Can P0762.224NLT be used as a direct replacement for PM3308-221M?

A: Yes. The P0762.224NLT matches all critical electrical parameters: 220 µH inductance, 400 mA current rating, 1.9Ohm maximum DC resistance, and ±20% tolerance. Physical dimensions are within manufacturing tolerance. The part is actively produced and ROHS3 compliant.

Q: What is the key difference between P0762.224NLT and AX97-20221?

A: The primary difference is DC resistance: P0762.224NLT maintains 1.9Ohm maximum (matching the original), while AX97-20221 provides 1.3Ohm maximum (improved performance). Operating temperature ranges differ: P0762.224NLT covers -40°C to 130°C; AX97-20221 covers -40°C to 85°C. Seated height also differs: P0762.224NLT is 0.118" (matching original); AX97-20221 is 0.138" (0.020" taller).

Q: Are there temperature considerations when substituting?

A: Yes. The original PM3308-221M operates from -55°C to 125°C. The P0762.224NLT operates from -40°C to 130°C, which covers the upper range but not the lower extreme. The AX97-20221 operates from -40°C to 85°C, which is more restrictive at both ends. Verify application temperature requirements before selection.

Q: Do package dimensions require PCB layout changes?

A: The P0762.224NLT dimensions (0.510" L x 0.370" W x 0.118" H) are within 0.002" of the original across all axes and require no layout modification. The AX97-20221 dimensions (0.530" L x 0.370" W x 0.138" H) add 0.020" to length and 0.020" to height. Verify PCB footprint and clearance zones accommodate these variations.

Q: What is the compliance status of each substitute?

A: The PM3308-221M is RoHS non-compliant. Both substitutes are ROHS3 compliant: P0762.224NLT and AX97-20221. All three parts are REACH unaffected and classified under ECCN EAR99.

Q: Can inductance tolerance be maintained across substitutes?

A: Yes. All three parts specify ±20% inductance tolerance at 100 kHz test frequency, ensuring consistent circuit performance across the tolerance band.

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