CDR74NP-181MC Equivalent & Substitute Parts

Part Overview

The CDR74NP-181MC is a 180 µH shielded surface mount inductor manufactured by Sumida America Components Inc. This component is rated for 380 mA continuous current with a maximum DC resistance of 970 mOhm and operates at a self-resonant frequency of 6.53 MHz. The part is classified as obsolete, making equivalent and substitute components necessary for ongoing design support and procurement.

Substitute parts must maintain the core electrical specifications: 180 µH inductance at 1 kHz test frequency, shielded construction, surface mount packaging, and compatibility with the nonstandard form factor. Mechanical dimensions and current handling capabilities are secondary selection criteria that may vary within acceptable engineering tolerances.

Substiute Parts

CDR74NP-181MC

Sumida America Components Inc.In Stock: 894CDR74NP-181MC Datasheet

Current PartRFQ

CDRH74NP-181MC-B

Sumida America Components Inc.In Stock: 2071CDRH74NP-181MC-B Datasheet

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SRR7045-181M

Bourns Inc.In Stock: 1926SRR7045-181M Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution logic for the CDR74NP-181MC is based on the following mandatory electrical and mechanical parameters:

Primary Substitution Criteria:

• Inductance value: 180 µH (fixed requirement)
• Inductance test frequency: 1 kHz (measurement standard)
• Inductance tolerance: ±20% or tighter (electrical performance window)
• Current rating: minimum 380 mA (thermal and saturation margin)
• DC resistance: 970 mOhm or lower (power loss consideration)
• Shielding: Shielded construction (electromagnetic containment)
• Mounting: Surface mount technology (assembly compatibility)

Secondary Considerations:

• Self-resonant frequency: 5 MHz or higher (frequency response margin)
• Package dimensions: Nonstandard form factor (mechanical fit)
• Product status: Active preferred over obsolete (supply continuity)
• RoHS3 compliance: Required (regulatory alignment)
• Moisture sensitivity: MSL 1 (handling and storage)

Two substitute parts meet these criteria with varying performance enhancements.

Parameter Comparison

Engineering Selection Recommendations

CDRH74NP-181MC-B (Sumida America Components Inc.)

This part is the direct successor within the Sumida product line. It maintains identical inductance (180 µH) and tolerance (±20%), with a marginal increase in current rating from 380 mA to 420 mA and DC resistance from 970 mOhm to 980 mOhm. The CDRH74NP-181MC-B is classified as active, ensuring long-term availability and supply chain stability. It is ROHS3 compliant with MSL 1 rating. Mechanical dimensions are slightly reduced (7.30mm x 7.30mm vs. 7.70mm x 7.10mm), which may require PCB layout verification. Operating temperature range is specified as -40°C to 100°C. This substitute is recommended for direct replacement in applications where the original CDR74NP-181MC is no longer procurable.

SRR7045-181M (Bourns Inc.)

This part offers superior electrical performance with a 660 mA current rating and 660 mOhm maximum DC resistance, representing a 31% reduction in resistance compared to the original. The SRR7045-181M is a drum core, wirewound inductor with documented saturation current (450 mA) and quality factor (52 @ 796 kHz). It is active in production with ROHS3 compliance and MSL 1 rating. Operating temperature extends to -40°C to 125°C. The inductance test frequency is 100 kHz rather than 1 kHz, and self-resonant frequency is specified at 5 MHz. Mechanical dimensions are the smallest of the three parts (7.00mm x 7.00mm). This substitute is suitable for applications requiring lower power dissipation and higher thermal margin, provided the different test frequency does not conflict with circuit design specifications.

Selection Basis:

Both substitutes maintain the mandatory 180 µH inductance, shielded construction, and surface mount configuration. The choice between CDRH74NP-181MC-B and SRR7045-181M depends on application requirements: select CDRH74NP-181MC-B for form factor consistency and direct Sumida compatibility; select SRR7045-181M for enhanced current handling and reduced DC resistance in power-sensitive applications.

Frequently Asked Questions (FAQ)

Q: Can the CDR74NP-181MC be replaced with either substitute without circuit redesign?

A: Both substitutes maintain the 180 µH inductance specification at their respective test frequencies (1 kHz for CDRH74NP-181MC-B, 100 kHz for SRR7045-181M). Circuit redesign is not required if the application operates within the specified current ratings and does not depend on the original self-resonant frequency of 6.53 MHz. Verify that the lower self-resonant frequency of the SRR7045-181M (5 MHz) does not conflict with high-frequency filtering requirements.

Q: What is the impact of the different DC resistance values?

A: The CDR74NP-181MC has 970 mOhm maximum resistance. The CDRH74NP-181MC-B has 980 mOhm (negligible difference), while the SRR7045-181M has 660 mOhm (31% lower). Lower DC resistance reduces power dissipation and heat generation. In current-limited applications, the SRR7045-181M will operate cooler. Verify that the application's thermal budget and current distribution can accommodate the lower resistance value.

Q: Are the mechanical dimensions compatible with the original PCB layout?

A: The CDR74NP-181MC measures 7.70mm x 7.10mm. The CDRH74NP-181MC-B measures 7.30mm x 7.30mm (slightly smaller in length, larger in width). The SRR7045-181M measures 7.00mm x 7.00mm (smallest footprint). Height differences are minimal (4.85mm, 4.50mm, and 4.80mm respectively). PCB layout verification is required, particularly for the CDRH74NP-181MC-B due to its square footprint, which may not align with the original rectangular pad pattern.

Q: What is the significance of the different inductance test frequencies?

A: The CDR74NP-181MC and CDRH74NP-181MC-B are tested at 1 kHz, while the SRR7045-181M is tested at 100 kHz. Inductance values can vary with frequency due to core material properties. Both test frequencies are standard in the industry. If the application operates at frequencies significantly different from the test frequency, consult the manufacturer's frequency response curves to confirm inductance stability.

Q: Are all three parts RoHS3 compliant?

A: Yes. The CDR74NP-181MC, CDRH74NP-181MC-B, and SRR7045-181M are all ROHS3 compliant. All three have MSL 1 (Unlimited) moisture sensitivity ratings, indicating no special storage or handling requirements.

Q: Which substitute should be selected for new designs?

A: For new designs, the CDRH74NP-181MC-B is recommended as the primary choice due to its active product status, direct Sumida lineage, and compatibility with the original specifications. The SRR7045-181M is recommended for applications where the enhanced current rating (660 mA vs. 380 mA) and lower DC resistance (660 mOhm vs. 970 mOhm) provide measurable performance benefits and where the different test frequency does not introduce circuit compatibility issues.

Q: What is the inventory status of these parts?

A: The CDR74NP-181MC (obsolete) has 825 pieces in stock. The CDRH74NP-181MC-B (active) has 2000 pieces in stock. The SRR7045-181M (active) has 1882 pieces in stock. For long-term procurement, prioritize active parts (CDRH74NP-181MC-B or SRR7045-181M) to ensure supply continuity beyond current inventory levels.