494R7SC Equivalent & Substitute Parts

Part Overview

The 494R7SC is a 4.7 µH shielded wirewound inductor manufactured by Murata Power Solutions Inc., designed for surface mount applications requiring high current handling and low DC resistance. This Active product is specified for 7.7 A continuous current with a maximum DC resistance of 12mOhm and operates across the temperature range of -40°C to 85°C. The component is housed in a nonstandard 4-lead package measuring 12.20mm × 12.20mm with a seated height of 8.00mm. Substitute parts are identified when equivalent inductance values, current ratings, and shielding characteristics align within acceptable tolerance ranges, enabling design flexibility and supply chain continuity.

Substiute Parts

494R7SC

Murata Power Solutions Inc.In Stock: 868494R7SC Datasheet

Current PartRFQ

SRR1280-4R7Y

Bourns Inc.In Stock: 1975SRR1280-4R7Y Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The SRR1280-4R7Y from Bourns Inc. qualifies as a direct substitute based on the following alignment of critical parameters:

• Inductance Match: Both parts specify 4.7 µH with ±30% tolerance
• Shielding Equivalence: Both are shielded designs, maintaining electromagnetic isolation requirements
• Current Capability: The substitute provides 8.2 A rating, exceeding the 7.7 A requirement of the main part
• DC Resistance: The substitute specifies 15.5mOhm maximum, which is within acceptable range for the same inductance class
• Surface Mount Compatibility: Both employ surface mount technology with nonstandard package configurations
• Regulatory Compliance: Both maintain ROHS3 compliance and REACH unaffected status
• Moisture Sensitivity: Both rated MSL 1 (Unlimited)

Substitution is valid when the application does not impose thermal constraints below -40°C or above 85°C, and when the physical footprint tolerance of ±0.3mm in length and width is acceptable.

Parameter Comparison

Engineering Selection Recommendations

Selection between the 494R7SC and SRR1280-4R7Y is determined by application-specific constraints:

Choose 494R7SC when:

• Lower DC resistance (12mOhm) is critical for minimizing power dissipation in current-limited applications
• Thermal environment is constrained to the -40°C to 85°C range
• Exact footprint matching to 12.20mm × 12.20mm is required by PCB layout

Choose SRR1280-4R7Y when:

• Extended operating temperature capability to 125°C is required
• Higher current margin (8.2 A vs. 7.7 A) provides design headroom
• Footprint tolerance of ±0.3mm is acceptable within PCB design rules
• Supply availability or lead time favors the Bourns component

Both parts maintain Active product status and equivalent regulatory compliance (ROHS3, REACH unaffected, EAR99 ECCN classification).

Frequently Asked Questions (FAQ)

Q: Can the SRR1280-4R7Y directly replace the 494R7SC on an existing PCB?

A: Physical replacement is possible if the PCB layout accommodates the 0.3mm increase in footprint dimensions (12.50mm vs. 12.20mm). The identical 8.00mm seated height ensures no clearance conflicts. Verify that trace routing and component spacing allow for the larger footprint before implementation.

Q: What is the impact of the 4.6mOhm increase in DC resistance?

A: At the rated 7.7 A current, the additional DC resistance increases power dissipation by approximately 0.22 W compared to the main part. This is acceptable in most applications but should be evaluated if thermal management is marginal or if the circuit operates continuously at maximum current.

Q: Are both parts suitable for high-frequency applications?

A: The 494R7SC exhibits a self-resonant frequency of 32MHz with Q of 42 @ 1MHz. The SRR1280-4R7Y has a self-resonant frequency of 30MHz with Q of 22 @ 7.96MHz. Both are suitable for standard switching power supply and filtering applications. Applications requiring specific Q characteristics should reference the detailed frequency response data.

Q: What is the significance of the ±30% inductance tolerance?

A: The ±30% tolerance means the actual inductance value may range from 3.29 µH to 6.11 µH. Both parts share this tolerance specification, ensuring equivalent circuit behavior within the tolerance band. Critical applications requiring tighter inductance control should specify matched pairs or request tighter tolerance grades if available.

Q: Are there any moisture or storage considerations?

A: Both parts are rated MSL 1 (Unlimited), indicating no moisture sensitivity restrictions. Standard dry storage conditions are recommended, and no special desiccant or humidity control is required during handling or storage.