6721-RC Equivalent & Substitute Parts

Part Overview

The Bourns 6721-RC is a 250 µH shielded toroidal inductor rated for 8 A continuous current with a maximum DC resistance of 41 mOhm. This through-hole component is designed for radial, vertical mounting with 4 open leads. The part is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production support.

Substiute Parts

6721-RC

Bourns Inc.In Stock: 9656721-RC Datasheet

Current PartRFQ

PT250-1800

API Delevan Inc.In Stock: 986PT250-1800 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 6721-RC is determined by the following critical parameters:

• Inductance Value: Must be 250 µH with ±15% tolerance
• Current Rating: Must meet or exceed 8 A
• DC Resistance: Must not exceed 41 mOhm maximum
• Core Material: Iron powder construction required
• Shielding: Shielded configuration required
• Mounting Type: Through-hole radial, vertical orientation
• Inductance Test Frequency: 1 kHz measurement standard

The API Delevan PT250-1800 meets all substitution criteria with equivalent inductance, core material, shielding, and mounting configuration. The substitute provides higher current rating (9.1 A) and operates within the same frequency test standard, making it functionally compatible for the 6721-RC application.

Parameter Comparison

Engineering Selection Recommendations

The PT250-1800 is the qualified substitute for the 6721-RC based on the following factors:

Product Status: The 6721-RC is obsolete, while the PT250-1800 is active and available in production quantities (906 pcs in stock). This ensures long-term supply continuity.

Electrical Compatibility: Both inductors share identical inductance values (250 µH) and tolerance specifications (±15%). The PT250-1800 provides superior current handling at 9.1 A versus the 6721-RC's 8 A rating, offering design margin for the same application envelope.

DC Resistance Trade-off: The PT250-1800 exhibits 55 mOhm maximum DC resistance compared to the 6721-RC's 41 mOhm. This 14 mOhm difference represents a 34% increase in resistive losses. Applications sensitive to power dissipation or thermal performance must evaluate this parameter against circuit requirements.

Compliance Status: The 6721-RC is ROHS3 compliant. The PT250-1800 is RoHS non-compliant. Design environments with RoHS mandates must account for this regulatory difference.

Physical Compatibility: Both components use radial, vertical through-hole mounting with open lead configurations, supporting direct PCB footprint compatibility.

Frequently Asked Questions (FAQ)

Q: Can the PT250-1800 directly replace the 6721-RC in existing designs?

A: Electrical substitution is valid based on matching inductance, tolerance, core material, and shielding. Physical footprint compatibility exists for radial, vertical through-hole mounting. However, the increased DC resistance (55 mOhm vs. 41 mOhm) and RoHS non-compliance status require circuit validation and regulatory assessment before implementation.

Q: What is the significance of the DC resistance difference between these inductors?

A: DC resistance directly affects power dissipation and thermal performance. At 8 A operation, the 6721-RC dissipates 2.624 W (8² × 0.041), while the PT250-1800 dissipates 4.62 W (8² × 0.055). Applications operating at maximum current ratings must verify thermal management capability with the substitute part.

Q: Are the physical dimensions compatible for PCB layout?

A: The 6721-RC measures 2.125" L × 1.100" W × 2.250" H (seated). The PT250-1800 measures 1.800" diameter × 0.770" W. While both use radial, vertical mounting, the dimensional differences require PCB footprint verification. The PT250-1800 is physically smaller, which may provide layout advantages.

Q: What compliance certifications apply to each part?

A: The 6721-RC is ROHS3 compliant and REACH unaffected. The PT250-1800 is RoHS non-compliant and REACH unaffected. Both parts carry EAR99 export classification and HTSUS code 8504.50.4000. Regulatory requirements for your application determine which part is acceptable.

Q: Is the higher current rating of the PT250-1800 (9.1 A vs. 8 A) a design advantage?

A: The PT250-1800's 9.1 A rating provides additional current margin above the 6721-RC's 8 A specification. This allows operation with reduced thermal stress and extended component life in applications approaching maximum current limits. However, this advantage does not offset the increased DC resistance penalty in power-sensitive designs.