70F273AI-RC Equivalent & Substitute Parts

Part Overview

The 70F273AI-RC is a 2.7 mH unshielded drum core wirewound inductor manufactured by Bourns Inc., rated for 57 mA maximum current with 45.6 Ohm DC resistance. This through-hole axial component operates across -55°C to 105°C and is designed for applications requiring fixed inductance in the 2.7 mH range at 250 kHz test frequency.

The 70F273AI-RC is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity and ensure component availability for production, repair, and redesign applications where this inductor specification is required.

Substiute Parts

70F273AI-RC

Bourns Inc.In Stock: 79670F273AI-RC Datasheet

Current PartRFQ

B78108S1275J000

EPCOS - TDK ElectronicsIn Stock: 1215B78108S1275J000 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 70F273AI-RC is determined by the following critical parameters:

• Inductance Value: Must be 2.7 mH ±5% tolerance
• Current Rating: Substitute must support minimum 57 mA operation
• DC Resistance: Substitute DCR must not exceed 45.6 Ohm to maintain circuit performance
• Core Configuration: Drum core wirewound construction with unshielded design
• Mounting and Package: Through-hole axial configuration for direct PCB compatibility
• Operating Temperature: Minimum range of -55°C ~ 105°C required
• Regulatory Compliance: ROHS3 compliance required

The substitute part B78108S1275J000 meets these substitution criteria with equivalent inductance, compatible current rating, lower DC resistance, and maintained through-hole axial form factor.

Parameter Comparison

Engineering Selection Recommendations

The B78108S1275J000 is a direct functional substitute for the 70F273AI-RC based on the following engineering criteria:

Inductance and Tolerance: Both components provide 2.7 mH inductance at ±5% tolerance, meeting the primary circuit requirement.

Current Capacity: The B78108S1275J000 provides 75 mA current rating, exceeding the 57 mA requirement of the original part, ensuring adequate headroom for circuit operation.

DC Resistance: The substitute exhibits 40 Ohm maximum DCR compared to 45.6 Ohm, representing a 12% improvement in resistance characteristics that reduces power dissipation.

Regulatory Compliance: Both components maintain ROHS3 compliance, satisfying environmental and regulatory requirements.

Product Availability: The B78108S1275J000 is classified as active product status with 1159 units in stock, providing reliable supply continuity compared to the obsolete 70F273AI-RC.

Physical Form Factor: Identical through-hole axial package configuration ensures direct PCB compatibility without layout modifications.

Operating Temperature: The substitute supports -55°C ~ 125°C range, extending the upper temperature limit by 20°C beyond the original specification.

Frequently Asked Questions (FAQ)

Q: Can the B78108S1275J000 directly replace the 70F273AI-RC without circuit modifications?

A: Yes. Both components share identical inductance value, tolerance, unshielded drum core configuration, and through-hole axial package. The substitute meets or exceeds all critical electrical parameters required for the original application.

Q: What is the significance of the core material difference (Iron vs. Ferrite)?

A: The core material difference reflects manufacturing variations between suppliers. Both iron and ferrite drum cores are suitable for unshielded wirewound inductors in this inductance range. The ferrite core in the substitute provides a higher self-resonant frequency (1 MHz vs. 880 kHz), which may improve performance in certain high-frequency applications.

Q: Does the lower DC resistance of the substitute affect circuit operation?

A: Lower DC resistance is beneficial. The 40 Ohm maximum DCR of the B78108S1275J000 compared to 45.6 Ohm reduces resistive losses and heat generation, improving overall circuit efficiency without altering inductance characteristics.

Q: Are there physical dimension differences between these components?

A: Yes. The B78108S1275J000 has smaller dimensions (0.157" Dia x 0.362" L) compared to the 70F273AI-RC (0.260" Dia x 0.380" L). Both maintain axial through-hole configuration, but PCB layout verification is recommended to confirm fit within existing component footprints.

Q: What is the difference in Q factor between these inductors?

A: The 70F273AI-RC provides Q of 50 at 250 kHz, while the B78108S1275J000 provides Q of 40 at 252 kHz. Higher Q indicates lower losses at the test frequency. Selection depends on circuit requirements for signal quality and bandwidth characteristics.

Q: Is the extended operating temperature range of the substitute beneficial?

A: The B78108S1275J000 supports -55°C ~ 125°C compared to -55°C ~ 105°C for the original part. This extended upper temperature limit provides additional thermal margin for applications operating in elevated ambient conditions or with higher component self-heating.