RXEF030 Polymeric PTC Resettable Fuse – Equivalent & Substitute Parts

Part Overview

The RXEF030 is a polymeric PTC resettable fuse manufactured by Littelfuse, rated for 72V maximum voltage with a 300 mA hold current. This component is designed for overcurrent protection in electronic circuits and automatically resets after a fault condition is cleared. The part is active in production with full compliance to ROHS3 and international safety certifications. Substitute parts are identified to address inventory availability, packaging preferences, or specific application requirements while maintaining electrical and mechanical compatibility.

Key Parameters

Parameter	Value
Voltage - Max	72V
Current - Hold (Ih) (Max)	300 mA
Current - Trip (It)	600 mA
Current - Max	40 A
Time to Trip	3 s
Resistance - Initial (Ri) (Min)	880 mOhms
Resistance - Post Trip (R1) (Max)	2.1 Ohms
Operating Temperature	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	Radial, Disc
Lead Spacing	0.200" (5.08mm)
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the RXEF030 are classified based on electrical parameter equivalence and mechanical compatibility. The critical parameters determining substitutability are: maximum voltage rating (72V), hold current (300 mA), trip current (600 mA), operating temperature range (-40°C ~ 85°C), and through-hole radial mounting configuration. Parts are grouped into direct equivalents (identical electrical specifications and packaging) and similar equivalents (matching electrical performance with minor packaging or dimensional variations).

Direct Equivalents: Parts with identical voltage, current, and resistance specifications, differing only in packaging format or lead spacing within acceptable tolerances.

Similar Equivalents: Parts meeting all critical electrical parameters but with different manufacturers or slight dimensional variations that do not affect circuit board compatibility.

Parameter Comparison

Part Number	Manufacturer	Voltage - Max	Current - Hold (Ih)	Current - Trip (It)	Resistance - Initial (Ri)	Resistance - Post Trip (R1)	Operating Temperature	Lead Spacing	Packaging	Approval Agency
RXEF030	Littelfuse	72V	300 mA	600 mA	880 mOhms	2.1 Ohms	-40°C ~ 85°C	0.200" (5.08mm)	Bag	CQC, CSA, TUV, UL
RXEF030S	Littelfuse	72V	300 mA	600 mA	880 mOhms	2.1 Ohms	-40°C ~ 85°C	0.199" (5.05mm)	Bag	CQC, CSA, TUV, UL
72R030XPR	Littelfuse Inc.	72V	300 mA	600 mA	880 mOhms	2.1 Ohms	-40°C ~ 85°C	0.201" (5.10mm)	Cut Tape (CT)	cURus, TUV
MF-RX030/72-0	Bourns Inc.	72V	300 mA	600 mA	760 mOhms	2.1 Ohms	-40°C ~ 85°C	0.201" (5.10mm)	Bulk	cURus, TUV
MF-R030	Bourns Inc.	60V	300 mA	600 mA	760 mOhms	2.1 Ohms	-40°C ~ 85°C	0.201" (5.10mm)	Bulk	cURus, TUV

Engineering Selection Recommendations

RXEF030S (Littelfuse): Direct substitute with identical electrical specifications and same manufacturer series. Lead spacing tolerance (0.199" vs 0.200") is within acceptable PCB hole pitch variation. Maintains full certification compliance (CQC, CSA, TUV, UL). Suitable for direct replacement in production environments.

72R030XPR (Littelfuse Inc.): Equivalent electrical performance with identical voltage and current ratings. Supplied in Cut Tape packaging rather than Bag format. Lead spacing (0.201") is within standard PCB tolerance. Certification includes cURus and TUV. Appropriate for automated assembly processes requiring tape packaging.

MF-RX030/72-0 (Bourns Inc.): Meets all critical electrical parameters with 72V rating and 300 mA hold current. Initial resistance (760 mOhms) is lower than RXEF030 (880 mOhms), resulting in reduced voltage drop during normal operation. Certifications include cURus and TUV. Suitable for applications where lower initial resistance is beneficial.

MF-R030 (Bourns Inc.): Voltage rating is 60V, which is below the RXEF030 specification of 72V. This part is not suitable for circuits designed for 72V operation and should only be considered for applications with maximum operating voltage of 60V or lower.

Frequently Asked Questions (FAQ)

Q: Can RXEF030S replace RXEF030 directly on the PCB? A: Yes. RXEF030S is a direct electrical equivalent with identical voltage, current, and resistance specifications. The lead spacing difference (0.199" vs 0.200") is within standard PCB manufacturing tolerances and does not affect mechanical fit.

Q: What is the difference between RXEF030 and 72R030XPR? A: Both parts have identical electrical specifications (72V, 300 mA hold current). The primary difference is packaging: RXEF030 is supplied in Bag format, while 72R030XPR is supplied in Cut Tape. The 72R030XPR is optimized for automated assembly lines. Certification coverage differs slightly (RXEF030 includes CSA and UL; 72R030XPR includes cURus).

Q: Is MF-RX030/72-0 compatible with RXEF030? A: Yes, for electrical performance. Both are rated 72V with 300 mA hold current and identical trip current. The MF-RX030/72-0 has lower initial resistance (760 mOhms vs 880 mOhms), which reduces power dissipation during normal operation. Mechanical fit is compatible with standard 5.08mm lead spacing PCBs.

Q: Why is MF-R030 listed as a substitute if it has a lower voltage rating? A: MF-R030 is not a suitable substitute for RXEF030 in 72V applications. It is rated for 60V maximum and should only be used in circuits with maximum operating voltage of 60V or lower. Exceeding the voltage rating will compromise device reliability.

Q: What certifications should I verify for my application? A: RXEF030 carries CQC, CSA, TUV, and UL certifications. If your application requires specific regional certifications, verify that the substitute part includes those certifications. For example, 72R030XPR includes cURus and TUV but not CSA or UL.

Q: Does lead spacing tolerance affect PCB compatibility? A: Lead spacing variations of ±0.01" (0.254mm) are within standard PCB manufacturing tolerances. RXEF030 (0.200"), RXEF030S (0.199"), 72R030XPR (0.201"), and MF-RX030/72-0 (0.201") are all compatible with standard 5.08mm pitch through-hole footprints.

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