PM20S-1R8K Equivalent & Substitute Parts

Part Overview

The PM20S-1R8K is a 1.8 µH shielded molded inductor manufactured by Bourns Inc., rated for 350 mA with a maximum DC resistance of 850mOhm. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The part is housed in a 1210 (3225 Metric) surface mount package and operates across the temperature range of -55°C to 125°C.

Key Parameters

Parameter	Value
Inductance	1.8 µH
Inductance Tolerance	±10%
Current Rating	350 mA
DC Resistance (DCR)	850mOhm Max
Shielding	Shielded
Core Material	Ferrite
Package / Case	1210 (3225 Metric)
Mounting Type	Surface Mount
Operating Temperature	-55°C ~ 125°C
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the PM20S-1R8K is determined by the following critical parameters:

Inductance Value: 1.8 µH (exact match required)
Current Rating: Minimum 350 mA (equal or higher acceptable)
DC Resistance: Maximum 850mOhm (lower values acceptable)
Core Material: Ferrite
Mounting Type: Surface Mount
Package Compatibility: 1210 (3225 Metric) or equivalent footprint dimensions
Operating Temperature Range: -55°C ~ 125°C minimum

The substitute parts identified maintain the core inductance specification and ferrite core material. Variations in shielding type, tolerance, and current rating are noted where they differ from the main part specification.

Parameter Comparison

Parameter	PM20S-1R8K (Main)	S1210-182K	CM322522-1R8KL	CM322522-1R8JL
Manufacturer	Bourns Inc.	API Delevan Inc.	Bourns Inc.	Bourns Inc.
Inductance	1.8 µH	1.8 µH	1.8 µH	1.8 µH
Inductance Tolerance	±10%	±10%	±10%	±5%
Current Rating (Amps)	350 mA	498 mA	200 mA	200 mA
DC Resistance (DCR)	850mOhm Max	650mOhm Max	820mOhm Max	820mOhm Max
Shielding	Shielded	Shielded	Unshielded	Unshielded
Core Type	Molded	-	Drum Core, Wirewound	Drum Core, Wirewound
Core Material	Ferrite	Ferrite	Ferrite	Ferrite
Q @ Freq	30 @ 7.96MHz	40 @ 7.9MHz	30 @ 7.96MHz	30 @ 7.96MHz
Frequency - Self Resonant	85MHz	95MHz	85MHz	85MHz
Operating Temperature	-55°C ~ 125°C	-55°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C
Package / Case	1210 (3225 Metric)	1210 (3225 Metric)	Nonstandard	Nonstandard
Product Status	Obsolete	Active	Active	Active
RoHS Status	RoHS non-compliant	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

S1210-182K (API Delevan Inc.) is the primary substitute for the PM20S-1R8K. This part maintains shielded construction, identical inductance value, matching 1210 package footprint, and exceeds the current rating requirement at 498 mA. The DC resistance of 650mOhm is lower than the 850mOhm maximum specification, providing improved performance characteristics. Operating temperature range matches the original specification. The part is currently in active production status. RoHS non-compliance status matches the original part.

CM322522-1R8KL and CM322522-1R8JL (Bourns Inc.) are secondary substitutes. Both parts maintain the 1.8 µH inductance and ferrite core material. However, these parts are unshielded drum core wirewound inductors with a nonstandard package designation. Current ratings of 200 mA fall below the 350 mA requirement of the main part, limiting their use to lower-current applications. Operating temperature minimum of -40°C does not meet the -55°C lower bound of the original specification. Both parts are ROHS3 compliant and in active production status.

Frequently Asked Questions (FAQ)

Q: Can S1210-182K directly replace PM20S-1R8K in all applications?

A: S1210-182K meets the critical substitution parameters: identical 1.8 µH inductance, shielded construction, 1210 package compatibility, and current rating exceeding 350 mA. The lower DC resistance (650mOhm vs. 850mOhm) is advantageous. Verify circuit design does not depend on the specific RoHS compliance status, as S1210-182K is RoHS non-compliant like the original part.

Q: Why are CM322522-1R8KL and CM322522-1R8JL listed as substitutes if they have lower current ratings?

A: These parts are listed as substitutes based on matching inductance value and core material. However, the 200 mA current rating is insufficient for applications requiring the full 350 mA capability of PM20S-1R8K. These parts are suitable only for circuits with current demands below 200 mA. Additionally, the -40°C to 125°C operating range does not support the full -55°C lower temperature specification.

Q: What is the impact of shielding differences between substitute parts?

A: PM20S-1R8K and S1210-182K are both shielded inductors, minimizing electromagnetic interference coupling to adjacent circuit elements. CM322522-1R8KL and CM322522-1R8JL are unshielded drum core inductors. In noise-sensitive applications or high-density PCB layouts, shielding differences may affect circuit performance. Unshielded inductors are suitable for applications where EMI coupling is not a design constraint.

Q: Are the nonstandard package dimensions of CM322522 parts compatible with 1210 footprints?

A: CM322522 parts have identical physical dimensions (0.126" L x 0.098" W, 3.20mm x 2.50mm) and height (0.087", 2.20mm) to the 1210 package. Despite the nonstandard package designation, footprint compatibility is maintained. Verify PCB layout and assembly equipment compatibility before implementation.

Q: What compliance considerations apply to substitute selection?

A: PM20S-1R8K is RoHS non-compliant. S1210-182K maintains RoHS non-compliant status. CM322522-1R8KL and CM322522-1R8JL are ROHS3 compliant. Design requirements for RoHS compliance will determine substitute eligibility. All parts are REACH unaffected and classified as EAR99 for export control purposes.

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