Bourns 5731 40µH Toroidal Inductor Equivalent & Substitute Parts

Part Overview

The Bourns 5731 is a 40µH unshielded toroidal inductor rated for 4A continuous current with a maximum DC resistance of 25mOhm. This through-hole component features an iron powder core and operates across the temperature range of -55°C to 105°C. The part is currently obsolete, making identification of suitable substitutes essential for ongoing design support and production continuity. Equivalent parts must maintain the same inductance value, current rating, and mounting configuration while meeting modern compliance standards.

Key Parameters

Parameter	Value
Inductance	40 µH
Current Rating	4 A
DC Resistance (DCR)	25 mOhm Max
Tolerance	±15%
Core Material	Iron Powder
Shielding	Unshielded
Mounting Type	Through Hole
Package / Case	Radial, Vertical (Open)
Operating Temperature	-55°C ~ 105°C

Substitute Part Grouping Explanation

Substitution eligibility for the Bourns 5731 is determined by the following critical parameters:

Inductance Value: Must be 40 µH (no deviation permitted)
Current Rating: Must support minimum 4 A continuous current
Mounting Configuration: Must be through-hole with radial, vertical (open) package
DC Resistance: Must not exceed 25 mOhm maximum to maintain electrical performance
Core Type: Iron powder core required for magnetic characteristics
Shielding: Unshielded configuration

Two substitute parts meet these criteria: the Bourns 5731-RC (same manufacturer, active product status) and the Pulse Electronics PE-92111NL (alternative manufacturer, active product status). Both maintain the specified inductance, current rating, and mounting type. Minor variations in DC resistance tolerance and operating temperature range are within acceptable engineering margins for this component category.

Parameter Comparison

Parameter	Bourns 5731	Bourns 5731-RC	Pulse Electronics PE-92111NL
Inductance	40 µH	40 µH	40 µH
Current Rating (Amps)	4 A	4 A	4 A
DC Resistance (DCR)	25 mOhm Max	25 mOhm Max	27 mOhm Max
Tolerance	±15%	±15%	±20%
Shielding	Unshielded	Unshielded	Unshielded
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	Radial, Vertical (Open)	Radial, Vertical (Open)	Radial, Vertical (Open)
Operating Temperature	-55°C ~ 105°C	-55°C ~ 105°C	-40°C ~ 130°C
Product Status	Obsolete	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Bourns 5731-RC is the primary substitute for the obsolete Bourns 5731. Both parts are manufactured by Bourns Inc., share identical electrical specifications (40µH, 4A, 25mOhm DCR, ±15% tolerance), and maintain the same through-hole radial vertical mounting configuration. The 5731-RC is currently in active production status with ROHS3 compliance, making it the preferred choice for new designs and production continuity. Packaging differs between the original (unspecified) and substitute (bulk), but electrical and mechanical compatibility is complete.

Pulse Electronics PE-92111NL serves as an alternative substitute when Bourns 5731-RC availability is constrained. This part maintains the same 40µH inductance, 4A current rating, and through-hole radial vertical package. The PE-92111NL exhibits slightly higher DC resistance (27mOhm max versus 25mOhm max) and broader inductance tolerance (±20% versus ±15%), with an extended operating temperature range (-40°C to 130°C). ROHS3 compliance is confirmed. The marginal increase in DCR and tolerance variation must be evaluated against specific circuit requirements before selection.

Frequently Asked Questions (FAQ)

Q: Can the Bourns 5731-RC directly replace the obsolete Bourns 5731 without circuit modification?

A: Yes. The 5731-RC maintains identical electrical specifications (40µH, 4A, 25mOhm DCR) and mechanical configuration (through-hole, radial vertical). No circuit redesign is required for direct substitution.

Q: What is the significance of the 2mOhm difference in DC resistance between the Bourns 5731-RC and Pulse Electronics PE-92111NL?

A: The PE-92111NL specifies 27mOhm maximum DCR compared to 25mOhm for the 5731-RC. This 2mOhm increase represents approximately 8% higher resistance. In applications where power dissipation or voltage drop across the inductor is critical, this difference must be calculated against circuit operating current to determine acceptability.

Q: Does the ±20% inductance tolerance of the PE-92111NL affect compatibility?

A: The PE-92111NL tolerance of ±20% is broader than the Bourns parts at ±15%. For circuits with tight inductance requirements (such as resonant frequency-dependent applications), the tighter tolerance of the Bourns 5731-RC is preferable. For general filtering and current-limiting applications, the ±20% tolerance is typically acceptable.

Q: Are there packaging differences between substitute parts?

A: The Bourns 5731-RC is supplied in bulk packaging, while the PE-92111NL is supplied in tray packaging. Both are through-hole components with identical radial vertical (open) case configuration. Packaging selection depends on assembly process requirements and inventory management practices.

Q: Which substitute part offers the widest operating temperature range?

A: The Pulse Electronics PE-92111NL operates from -40°C to 130°C, providing a 25°C extension at the upper temperature limit compared to the Bourns parts (-55°C to 105°C). For applications requiring extended high-temperature operation, the PE-92111NL is the appropriate selection.

Q: Are both substitute parts RoHS compliant?

A: Yes. Both the Bourns 5731-RC and Pulse Electronics PE-92111NL are ROHS3 compliant, meeting current environmental and regulatory requirements. The original Bourns 5731 is RoHS non-compliant.

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