PM75-121K Equivalent & Substitute Parts

Part Overview

The PM75-121K is a 120 µH unshielded drum core wirewound inductor manufactured by Bourns Inc., rated for 660 mA with a maximum DC resistance of 470mOhm. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The part operates across a temperature range of -30°C to 100°C and is mounted as a surface mount device in a nonstandard package measuring 7.80mm × 7.80mm.

Substiute Parts

PM75-121K

Bourns Inc.In Stock: 674PM75-121K Datasheet

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SDR0805-121KL

Bourns Inc.In Stock: 9373SDR0805-121KL Datasheet

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CR75NP-121KC

Sumida America Components Inc.In Stock: 1192CR75NP-121KC Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the PM75-121K are qualified based on the following critical parameters that determine functional equivalence:

• Inductance value: 120 µH (exact match required)
• Tolerance: ±10% (matching specification)
• Current rating: 660 mA minimum
• DC resistance: Within acceptable operating limits
• Core type: Ferrite, unshielded drum core
• Package footprint: 7.80mm × 7.80mm surface mount
• Mounting compatibility: Surface mount technology

The SDR0805-121KL and CR75NP-121KC meet these substitution criteria while maintaining electrical and mechanical compatibility with the original PM75-121K design.

Parameter Comparison

Engineering Selection Recommendations

The SDR0805-121KL is the primary direct substitute for the PM75-121K. Both are manufactured by Bourns Inc. and share identical inductance, tolerance, current rating, and package footprint specifications. The SDR0805-121KL offers an extended operating temperature range (-40°C to 125°C versus -30°C to 100°C) and is ROHS3 compliant, addressing regulatory requirements that the obsolete PM75-121K does not meet. DC resistance is marginally higher at 480mOhm compared to 470mOhm, which remains within acceptable design tolerances for most applications.

The CR75NP-121KC, manufactured by Sumida America Components Inc., serves as an alternative substitute. It matches the original DC resistance specification at 470mOhm and maintains the same inductance and current rating. The CR75NP-121KC has a slightly different package width (7.00mm versus 7.80mm) and maximum height (5.50mm versus 5.30mm), requiring verification of PCB layout compatibility. This part is also ROHS3 compliant and supports an extended temperature range (-40°C to 100°C).

For new designs and production continuity, the SDR0805-121KL is recommended due to its direct manufacturer match with Bourns Inc., superior temperature range, and full regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can the SDR0805-121KL be used as a direct replacement for the PM75-121K without PCB modifications?

A: Yes. Both parts share identical inductance (120 µH), tolerance (±10%), current rating (660 mA), and package footprint (7.80mm × 7.80mm). The SDR0805-121KL can be substituted without PCB layout changes. The DC resistance difference (480mOhm versus 470mOhm) is negligible for most circuit applications.

Q: What are the key differences between the SDR0805-121KL and CR75NP-121KC?

A: Both parts meet the core electrical specifications of the PM75-121K. The SDR0805-121KL is manufactured by Bourns Inc. (same as the original) and has identical package dimensions. The CR75NP-121KC is manufactured by Sumida America Components Inc., has a slightly narrower width (7.00mm versus 7.80mm), and a marginally taller maximum height (5.50mm versus 5.30mm). Both are ROHS3 compliant and support extended temperature ranges.

Q: Does the DC resistance difference between parts affect circuit performance?

A: The PM75-121K and CR75NP-121KC both specify 470mOhm maximum DC resistance, while the SDR0805-121KL specifies 480mOhm. This 10mOhm difference represents a 2.1% variance and is typically insignificant in inductor applications. Verify against your specific circuit requirements if DC resistance is a critical design parameter.

Q: Are all substitute parts available in the same packaging format?

A: No. The PM75-121K is supplied in bulk packaging. Both the SDR0805-121KL and CR75NP-121KC are supplied in Tape & Reel (TR) format, which is standard for production environments and offers advantages in automated assembly processes.

Q: What is the impact of the extended temperature range on substitute part selection?

A: Both substitute parts support extended operating temperature ranges compared to the obsolete PM75-121K. The SDR0805-121KL operates from -40°C to 125°C, and the CR75NP-121KC operates from -40°C to 100°C. If your application operates within the original PM75-121K temperature range (-30°C to 100°C), both substitutes are suitable. For applications requiring temperatures below -30°C or above 100°C, the SDR0805-121KL provides additional margin.

Q: Is RoHS compliance a factor in selecting a substitute?

A: Yes. The PM75-121K is RoHS non-compliant, while both substitute parts (SDR0805-121KL and CR75NP-121KC) are ROHS3 compliant. For new designs and production environments subject to RoHS regulations, either substitute part is required.