HM78D-7553R3MLFTR Equivalent & Substitute Parts

Part Overview

The HM78D-7553R3MLFTR is a shielded 2-coil inductor array manufactured by TT Electronics/BI Magnetics, designed for surface mount applications requiring dual inductance configurations. This component provides 3.3 µH inductance when coils are connected in parallel and 13.58 µH when connected in series. The part is currently discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives that maintain the same electrical and mechanical specifications for continued system support and new design implementations.

Substiute Parts

HM78D-7553R3MLFTR

TT Electronics/BI MagneticsIn Stock: 1844HM78D-7553R3MLFTR Datasheet

Current PartRFQ

SRF0703-3R3M

Bourns Inc.In Stock: 2693SRF0703-3R3M Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the HM78D-7553R3MLFTR is determined by strict equivalence across the following critical parameters:

Electrical Equivalence Criteria:

• Inductance value in parallel configuration: 3.3 µH
• Inductance value in series configuration: 13.2 µH to 13.58 µH (within ±20% tolerance band)
• Tolerance specification: ±20%
• Current rating capability in parallel configuration: minimum 3.31 A
• Operating temperature range: -40°C to 125°C minimum

Mechanical Equivalence Criteria:

• Number of coils: 2
• Shielding: Shielded construction
• Mounting type: Surface Mount
• Package footprint compatibility: 7.60 mm to 7.70 mm length and width
• Moisture sensitivity level: MSL 1 or better

Compliance Criteria:

• REACH Status: REACH Unaffected
• ECCN classification: EAR99

The SRF0703-3R3M meets all substitution criteria and is classified as a direct equivalent.

Parameter Comparison

Engineering Selection Recommendations

The SRF0703-3R3M from Bourns Inc. is a direct functional substitute for the discontinued HM78D-7553R3MLFTR. Selection of this substitute is supported by the following factors:

Product Availability: The SRF0703-3R3M maintains active product status with 2600 units in stock, providing reliable supply continuity for the discontinued HM78D-7553R3MLFTR.

Electrical Specifications: Both components share identical parallel inductance (3.3 µH) and series inductance values within the ±20% tolerance specification (13.2 µH vs. 13.58 µH). Operating temperature ranges are identical at -40°C to 125°C.

Mechanical Compatibility: Footprint dimensions are compatible (7.60 mm vs. 7.70 mm), with the substitute providing a lower profile height (3.60 mm vs. 4.80 mm). Both components are shielded, dual-coil surface mount inductors with MSL 1 ratings.

Compliance Status: Both components maintain REACH Unaffected status and EAR99 ECCN classification. The SRF0703-3R3M provides additional ROHS3 compliance certification.

Performance Considerations: The substitute exhibits higher DC resistance in both configurations (31.6 mOhm parallel vs. 18.3 mOhm; 182 mOhm series vs. 73.2 mOhm) and lower current ratings (3.31 A parallel vs. 3.94 A; 1.66 A series vs. 1.97 A). These differences must be evaluated against specific circuit requirements to confirm suitability for the intended application.

Frequently Asked Questions (FAQ)

Q: Can the SRF0703-3R3M be used as a direct replacement for the HM78D-7553R3MLFTR?

A: The SRF0703-3R3M is functionally equivalent for applications requiring 3.3 µH parallel inductance and 13.2 µH series inductance within ±20% tolerance. However, the higher DC resistance and lower current ratings of the substitute must be verified against circuit design specifications before implementation.

Q: What are the key differences between these two components?

A: The primary differences are: (1) DC resistance is higher in the SRF0703-3R3M (31.6 mOhm parallel vs. 18.3 mOhm; 182 mOhm series vs. 73.2 mOhm), (2) current ratings are lower (3.31 A vs. 3.94 A parallel; 1.66 A vs. 1.97 A series), (3) the substitute has a lower profile (3.60 mm vs. 4.80 mm), and (4) the substitute provides ROHS3 compliance certification.

Q: Are the footprints compatible?

A: Yes. The HM78D-7553R3MLFTR measures 7.70 mm x 7.70 mm, while the SRF0703-3R3M measures 7.60 mm x 7.60 mm. These dimensions are compatible for standard PCB layouts. The lower height of the substitute (3.60 mm vs. 4.80 mm) may provide additional clearance benefits.

Q: Does the higher DC resistance of the substitute affect circuit performance?

A: The SRF0703-3R3M exhibits approximately 1.7 times higher DC resistance in parallel configuration and 2.5 times higher in series configuration. Applications sensitive to resistive losses or thermal dissipation must evaluate whether this increase is acceptable for the intended circuit function.

Q: What is the current handling capability difference?

A: The SRF0703-3R3M is rated for 3.31 A in parallel configuration compared to 3.94 A for the original part, and 1.66 A in series configuration compared to 1.97 A. Circuits operating near maximum current specifications must confirm the substitute's lower ratings are sufficient.

Q: Are both components available in the same packaging formats?

A: The HM78D-7553R3MLFTR is supplied in Cut Tape (CT) packaging. The SRF0703-3R3M is available in both Cut Tape (CT) and Digi-Reel® packaging options, providing additional supply flexibility.

Q: What compliance certifications apply to each component?

A: Both components maintain REACH Unaffected status and EAR99 ECCN classification. The SRF0703-3R3M provides additional ROHS3 compliance certification. Both components have MSL 1 (Unlimited) moisture sensitivity ratings.

Q: Is the SRF0703-3R3M suitable for the same operating temperature range?

A: Yes. Both components are rated for -40°C to 125°C operating temperature range, providing equivalent thermal performance specifications.