PM20-121K Equivalent & Substitute Parts Reference

Part Overview

The PM20-121K is a 120 µH unshielded molded inductor manufactured by Bourns Inc., rated for 70 mA maximum current with 11Ohm maximum DC resistance in a 1210 (3225 Metric) surface mount package. This part is classified as obsolete, making identification of equivalent and substitute components essential for ongoing design support and procurement continuity. Substitute parts must maintain electrical compatibility across inductance value, current rating, DC resistance, and operating temperature range while accommodating packaging and compliance differences.

Substiute Parts

PM20-121K

Bourns Inc.In Stock: 1065PM20-121K Datasheet

Current PartRFQ

CM322522-121KL

Bourns Inc.In Stock: 891CM322522-121KL Datasheet

SimilarRFQ

CM322522-R12ML

Bourns Inc.In Stock: 821CM322522-R12ML Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the PM20-121K are evaluated based on the following critical parameters that determine functional equivalence:

Primary Electrical Criteria:

• Inductance value: 120 µH (±10% tolerance acceptable)
• Current rating: minimum 70 mA
• DC resistance: maximum 11Ohm
• Operating temperature range: must support -55°C ~ 125°C or equivalent industrial range
• Shielding configuration: unshielded
• Core material: ferrite

Secondary Criteria:

• Mounting type: surface mount
• Physical footprint: 1210 (3225 Metric) or compatible dimensions
• Frequency characteristics: Q factor and self-resonant frequency within application tolerance

The substitute parts identified below meet the primary electrical criteria but exhibit variations in product status, packaging format, and regulatory compliance that must be evaluated against specific application requirements.

Parameter Comparison

Engineering Selection Recommendations

CM322522-121KL Evaluation: This part maintains identical inductance (120 µH), inductance tolerance (±10%), DC resistance (11Ohm max), and frequency characteristics (Q @ 796kHz, 10MHz SRF) as the PM20-121K. However, the current rating is reduced to 55 mA, which is below the original 70 mA specification. This part is suitable only for applications where the actual operating current does not exceed 55 mA. The part is active and ROHS3 compliant, providing improved regulatory status and long-term availability compared to the obsolete PM20-121K. Operating temperature range is reduced to -40°C ~ 125°C, which may be limiting for extended temperature applications.

CM322522-R12ML Evaluation: This part is not electrically equivalent to the PM20-121K. The inductance value is 120 nH (not 120 µH), representing a 1000-fold reduction in inductance. While the current rating (240 mA) and DC resistance (670mOhm) differ significantly, the fundamental inductance mismatch disqualifies this part as a direct substitute. This part operates at substantially different frequency characteristics (10 @ 25.2MHz, 400MHz SRF) and is suitable only for applications requiring nanohenry-range inductance values.

Recommendation Summary: For direct electrical substitution of the PM20-121K in applications operating at or below 55 mA, CM322522-121KL is the appropriate choice, provided the reduced operating temperature minimum (-40°C vs. -55°C) is acceptable. For applications requiring the full 70 mA current rating or extended low-temperature operation, alternative sourcing or design modification is necessary. CM322522-R12ML is not suitable as a substitute for this application.

Frequently Asked Questions (FAQ)

Q: Can CM322522-121KL be used as a direct replacement for PM20-121K? A: CM322522-121KL is electrically compatible for inductance, tolerance, DC resistance, and frequency response. However, the current rating is reduced from 70 mA to 55 mA. Direct substitution is valid only if circuit operating current does not exceed 55 mA. The operating temperature minimum is also reduced from -55°C to -40°C.

Q: Why is CM322522-R12ML listed as a substitute if the inductance is different? A: CM322522-R12ML is not a functional substitute for the PM20-121K. The inductance value differs by three orders of magnitude (120 nH vs. 120 µH). This part was included in the source data but does not meet substitution criteria for this application.

Q: What are the key differences between the PM20-121K and CM322522-121KL? A: The primary differences are: (1) current rating reduced from 70 mA to 55 mA, (2) operating temperature minimum reduced from -55°C to -40°C, (3) core construction changed from molded to drum core wirewound, (4) package classification changed from standard 1210 to nonstandard, and (5) RoHS compliance improved from non-compliant to ROHS3 compliant.

Q: Are the physical dimensions identical between PM20-121K and CM322522-121KL? A: Yes. Both parts measure 3.20mm x 2.50mm x 2.20mm (height seated max). Despite different package classifications (standard 1210 vs. nonstandard), the physical footprint is identical.

Q: What is the impact of the core type change from molded to drum core wirewound? A: The core type change affects mechanical construction and thermal characteristics but does not alter the electrical specifications provided (inductance, tolerance, DC resistance, Q factor, and self-resonant frequency). Application-specific factors such as vibration resistance, thermal cycling, or EMI performance may be affected and should be evaluated for critical applications.

Q: Is the reduced operating temperature range of CM322522-121KL a concern? A: The reduced minimum temperature (-40°C vs. -55°C) is relevant only for applications requiring operation below -40°C. For standard industrial temperature ranges (-40°C to 125°C), this is not a limiting factor. For military or aerospace applications requiring -55°C operation, alternative solutions are necessary.

Q: What is the significance of the packaging format change from standard to Tape & Reel? A: Tape & Reel (TR) packaging is standard for automated assembly processes and does not affect component functionality. This format change typically improves handling efficiency and cost for high-volume production. For low-volume or manual assembly, reel format may require additional handling considerations.