Bourns 77F270K Equivalent & Substitute Parts

Part Overview

The Bourns 77F270K is a 27 µH unshielded drum core wirewound inductor rated for 390 mA with a maximum DC resistance of 940 mOhm. This through-hole axial component operates across a temperature range of -55°C to 105°C and is designed for applications requiring fixed inductance in compact form factors.

The 77F270K carries an obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements for systems utilizing this inductor.

Substiute Parts

77F270K

Bourns Inc.In Stock: 80677F270K Datasheet

Current PartRFQ

IRF36ER270K

Vishay DaleIn Stock: 872IRF36ER270K Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the Bourns 77F270K are identified based on strict electrical and mechanical parameter matching. The following criteria determine substitution eligibility:

Critical Matching Parameters:

• Inductance value: 27 µH
• Inductance tolerance: ±10%
• Current rating: 390 mA minimum
• DC resistance: 940 mOhm maximum
• Core material: Ferrite
• Shielding: Unshielded
• Mounting type: Through hole
• Package style: Axial
• Operating temperature range: -55°C to 105°C minimum

Parts meeting all these specifications are classified as direct substitutes. Variations in secondary parameters such as Q factor or self-resonant frequency do not disqualify a part if primary electrical and mechanical specifications align.

Parameter Comparison

Engineering Selection Recommendations

Bourns 77F270K Status: Obsolete product. Direct replacement is required for new procurement or continued system support.

Vishay Dale IRF36ER270K Suitability: The IRF36ER270K matches the primary electrical specifications (27 µH inductance, 390 mA current rating, 940 mOhm DC resistance) and mechanical configuration (through-hole axial package, unshielded ferrite core). This part is suitable as a functional equivalent for the obsolete Bourns 77F270K.

Selection between available substitutes should be based on:

• Inventory availability and lead time
• Compliance certifications applicable to the end application
• PCB layout compatibility with axial through-hole mounting
• Thermal management requirements within the specified operating temperature range

Frequently Asked Questions (FAQ)

Q: Can the Vishay Dale IRF36ER270K directly replace the Bourns 77F270K in existing designs?

A: Yes, provided that the inductance value (27 µH), current rating (390 mA), and DC resistance (940 mOhm maximum) requirements are met. Both parts feature identical axial through-hole packaging and unshielded ferrite core construction, allowing direct PCB substitution without layout modification.

Q: What parameters must remain constant when selecting a substitute inductor?

A: The inductance value (27 µH ±10%), current rating (390 mA minimum), DC resistance (940 mOhm maximum), core type (ferrite, unshielded), and mounting configuration (through-hole axial) must match or exceed the original specification. Operating temperature range must support the application's thermal requirements.

Q: Are there any compliance or certification differences between the Bourns 77F270K and its substitutes?

A: Compliance information for substitute parts must be verified against the specific application requirements. The Bourns 77F270K is RoHS non-compliant. Substitute part compliance status should be confirmed with the manufacturer or distributor before final selection.

Q: How does the axial package affect component placement?

A: Axial through-hole inductors require two mounting holes aligned along the component's length. PCB footprints must accommodate the 0.157" diameter and 0.410" length dimensions. Substitute parts with identical axial packaging can use the same footprint without modification.

Q: What is the significance of the Q factor and self-resonant frequency?

A: The Q factor (55 @ 2.52 MHz) and self-resonant frequency (7.6 MHz) indicate the inductor's performance characteristics at specific frequencies. These parameters should be considered for high-frequency applications but do not disqualify substitutes if primary electrical specifications are met.