RUE250U-2 Equivalent & Substitute Parts

Part Overview

The RUE250U-2 is a Polymeric PTC Resettable Fuse manufactured by Littelfuse, rated for 30V maximum voltage and 2.5A hold current. This component is classified as Obsolete, making equivalent and substitute parts necessary for ongoing system support and new designs. The PolySwitch® series provides automatic overcurrent protection through polymeric positive temperature coefficient technology, resetting after fault conditions are cleared.

Key Parameters

Parameter	Value
Voltage - Max	30V
Current - Hold (Ih) (Max)	2.5 A
Current - Trip (It)	5 A
Time to Trip	10.3 s
Resistance - Initial (Ri) (Min)	20 mOhms
Resistance - Post Trip (R1) (Max)	70 mOhms
Operating Temperature	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	Radial, Disc

Substitute Part Grouping Explanation

Substitution for the RUE250U-2 is determined by strict equivalence across the following critical parameters:

Voltage - Max: 30V
Current - Hold (Ih) (Max): 2.5 A
Current - Trip (It): 5 A
Time to Trip: 10.3 s
Resistance - Initial (Ri) (Min): 20 mOhms
Resistance - Post Trip (R1) (Max): 70 mOhms
Operating Temperature: -40°C ~ 85°C
Mounting Type: Through Hole
Package / Case: Radial, Disc

All substitute parts listed maintain these core electrical and mechanical specifications. Variations in physical dimensions, lead spacing, maximum current ratings, and compliance certifications do not affect functional substitutability within the defined parameter set.

Parameter Comparison

Parameter	RUE250U-2	RUEF250-2	RUEF250U-2	PTR030V0250-TR
Manufacturer	Littelfuse	Littelfuse Inc.	Littelfuse	Eaton - Electronics Division
Product Status	Obsolete	Active	Active	Active
Voltage - Max	30V	30V	30V	30V
Current - Hold (Ih) (Max)	2.5 A	2.5 A	2.5 A	2.5 A
Current - Trip (It)	5 A	5 A	5 A	5 A
Time to Trip	10.3 s	10.3 s	10.3 s	10.3 s
Resistance - Initial (Ri) (Min)	20 mOhms	20 mOhms	20 mOhms	20 mOhms
Resistance - Post Trip (R1) (Max)	70 mOhms	70 mOhms	70 mOhms	70 mOhms
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	Radial, Disc	Radial, Disc	Radial, Disc	Radial, Disc
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

All three substitute parts—RUEF250-2, RUEF250U-2, and PTR030V0250-TR—are functionally equivalent to the obsolete RUE250U-2 based on core electrical and mechanical parameters. Selection should prioritize Active product status and compliance requirements:

RUEF250-2 and RUEF250U-2 are both Active Littelfuse products with ROHS3 compliance and expanded approval certifications (CQC, CSA, TUV, UL). RUEF250U-2 offers a more compact physical footprint while maintaining identical electrical specifications.

PTR030V0250-TR is an Active Eaton product with ROHS3 compliance and cURus/TUV certifications, providing an alternative from a different manufacturer with equivalent performance characteristics.

Frequently Asked Questions (FAQ)

Q: Can RUEF250-2 directly replace RUE250U-2 in existing designs?

A: Yes. Both parts share identical electrical specifications: 30V maximum voltage, 2.5A hold current, 5A trip current, and 10.3s trip time. Physical dimensions differ slightly, but both are Through Hole Radial, Disc packages suitable for standard PCB mounting.

Q: What is the difference between RUEF250-2 and RUEF250U-2?

A: Both are Littelfuse Active products with identical electrical ratings. RUEF250U-2 has a smaller physical footprint (7.60mm x 2.80mm versus 11.40mm x 3.00mm) and slightly different lead spacing (0.199" versus 0.199"). Selection depends on available PCB space and lead spacing requirements.

Q: Is PTR030V0250-TR from Eaton compatible with the RUE250U-2 circuit?

A: Yes. The PTR030V0250-TR maintains all critical electrical parameters: 30V voltage rating, 2.5A hold current, 5A trip current, and 10.3s trip time. It is manufactured by Eaton - Electronics Division and carries ROHS3 compliance with cURus and TUV certifications.

Q: Why is RUE250U-2 marked as Obsolete?

A: The RUE250U-2 is no longer in active production. Active alternatives from Littelfuse (RUEF250-2, RUEF250U-2) and Eaton (PTR030V0250-TR) provide equivalent functionality with current manufacturing support and compliance certifications.

Q: Are there compliance differences between the substitute parts?

A: Yes. RUE250U-2 is RoHS non-compliant. All three substitutes (RUEF250-2, RUEF250U-2, PTR030V0250-TR) are ROHS3 compliant. RUEF parts carry CQC, CSA, TUV, and UL certifications, while PTR030V0250-TR carries cURus and TUV certifications.

Q: What is the lead spacing tolerance for these parts?

A: RUE250U-2 has 0.201" (5.10mm) lead spacing. RUEF250-2 and RUEF250U-2 have 0.199" (5.05mm) lead spacing. PTR030V0250-TR has 0.197" (5.00mm) lead spacing. These minor variations are within standard PCB design tolerances for Through Hole components.

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