MF-RG500-AP Equivalent & Substitute Parts

Part Overview

The MF-RG500-AP is a polymeric PTC resettable fuse manufactured by Bourns Inc. in the Multifuse® MF-RG series. This through-hole radial disc component is rated for 16V maximum voltage with a 5A hold current and 8.5A trip current. The part is active in production status and widely used in circuit protection applications requiring automatic reset capability after fault conditions clear.

Equivalent and substitute parts are necessary when the primary part is unavailable, when alternative packaging formats are required, or when sourcing from multiple manufacturers is needed for supply chain resilience.

Key Parameters

Parameter	Value
Voltage - Max	16V
Current - Hold (Ih) (Max)	5 A
Current - Trip (It)	8.5 A
Current - Max	100 A
Time to Trip	2 s
Resistance - Initial (Ri) (Min)	15 mOhms
Resistance - Post Trip (R1) (Max)	34 mOhms
Operating Temperature	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	Radial, Disc
Lead Spacing	0.201" (5.10mm)
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the MF-RG500-AP is determined by the following critical parameters:

Voltage Rating: Maximum voltage must be 16V or greater
Current - Hold (Ih): Must be rated for 5A hold current
Current - Trip (It): Must be rated for 8.5A trip current
Mounting Type: Must be through-hole radial disc configuration
Lead Spacing: Must accommodate 0.201" (5.10mm) spacing or compatible PCB layouts
Operating Temperature Range: Must support -40°C to 85°C minimum
Compliance: Must maintain ROHS3 compliance and REACH unaffected status

Parts are grouped into two categories:

Parametric Equivalents: Parts with identical electrical specifications (voltage, current ratings, trip characteristics, and resistance values) and identical physical form factor.

Similar Substitutes: Parts with identical voltage and current ratings but different physical dimensions or packaging formats, suitable for applications where form factor flexibility exists.

Parameter Comparison

Parameter	MF-RG500-AP (Bourns)	16R500GPR (Littelfuse)	RGEF500 (Littelfuse)	RGEF300-2 (Littelfuse)
Manufacturer	Bourns Inc.	Littelfuse Inc.	Littelfuse	Littelfuse
Series	Multifuse® MF-RG	POLY-FUSE® 16R	PolySwitch® RGEF	PolySwitch® RGEF
Voltage - Max	16V	16V	16V	16V
Current - Hold (Ih) (Max)	5 A	5 A	5 A	3 A
Current - Trip (It)	8.5 A	8.5 A	8.5 A	5.1 A
Time to Trip	2 s	2 s	2 s	1 s
Resistance - Initial (Ri) (Min)	15 mOhms	15 mOhms	15 mOhms	38 mOhms
Resistance - Post Trip (R1) (Max)	34 mOhms	34 mOhms	34 mOhms	97.5 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
Size / Dimension	0.409" L x 0.118" W (10.40mm x 3.00mm)	0.409" L x 0.118" W (10.40mm x 3.00mm)	0.390" L x 0.098" W (9.90mm x 2.50mm)	0.260" L x 0.098" W (6.60mm x 2.50mm)
Height - Seated (Max)	0.563" (14.30mm)	0.563" (14.30mm)	0.563" (14.30mm)	0.433" (11.00mm)
Lead Spacing	0.201" (5.10mm)	0.201" (5.10mm)	0.199" (5.05mm)	0.199" (5.05mm)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Approval Agency	Not specified	cURus, TUV	CSA, TUV, UL	CSA, TUV, UL
Packaging	Tape & Box (TB)	Cut Tape (CT)	Bag	Cut Tape (CT)

Engineering Selection Recommendations

16R500GPR (Littelfuse POLY-FUSE® 16R Series) is the primary parametric equivalent. This part maintains identical electrical specifications, physical dimensions, lead spacing, and height characteristics. Both parts are ROHS3 compliant and REACH unaffected. The 16R500GPR carries additional certifications (cURus, TUV) and is available in Cut Tape packaging format.

RGEF500 (Littelfuse PolySwitch® RGEF Series) is a direct electrical equivalent with identical voltage, current, and resistance specifications. Physical dimensions differ slightly (0.390" L vs. 0.409" L and 0.098" W vs. 0.118" W), and lead spacing is 0.199" versus 0.201". This part is suitable for applications where minor dimensional variations are acceptable. RGEF500 carries CSA, TUV, and UL certifications and is available in Bag packaging.

RGEF300-2 (Littelfuse PolySwitch® RGEF Series) is not a direct equivalent. This part has reduced current ratings (3A hold vs. 5A hold, 5.1A trip vs. 8.5A trip) and higher resistance values. RGEF300-2 is suitable only for applications with lower current requirements and cannot be used as a direct replacement for the MF-RG500-AP in circuits designed for 5A operation.

Frequently Asked Questions (FAQ)

Q: Can RGEF500 be used as a direct replacement for MF-RG500-AP?

A: RGEF500 is electrically equivalent with identical voltage, current, and resistance specifications. Physical dimensions differ slightly (length 0.390" vs. 0.409", width 0.098" vs. 0.118"). Lead spacing is 0.199" versus 0.201", a difference of 0.002". Compatibility depends on PCB layout tolerances. Verify that the PCB footprint accommodates the dimensional variation before substitution.

Q: Is RGEF300-2 compatible with MF-RG500-AP applications?

A: No. RGEF300-2 has reduced current ratings (3A hold, 5.1A trip) compared to MF-RG500-AP (5A hold, 8.5A trip). This part is not suitable for circuits designed for 5A operation and will trip prematurely under normal operating conditions.

Q: What are the key differences between 16R500GPR and MF-RG500-AP?

A: 16R500GPR is a parametric equivalent with identical electrical and physical specifications. The primary differences are manufacturer (Littelfuse vs. Bourns), series designation (POLY-FUSE® 16R vs. Multifuse® MF-RG), packaging format (Cut Tape vs. Tape & Box), and certifications (cURus, TUV vs. not specified).

Q: Are all substitute parts ROHS3 compliant?

A: Yes. MF-RG500-AP, 16R500GPR, RGEF500, and RGEF300-2 are all ROHS3 compliant and REACH unaffected.

Q: What packaging formats are available?

A: MF-RG500-AP is supplied in Tape & Box (TB) format. 16R500GPR is available in Cut Tape (CT). RGEF500 is available in Bag format. RGEF300-2 is available in Cut Tape (CT). Select packaging based on assembly process requirements and inventory management needs.

Q: Can dimensional differences affect PCB assembly?

A: Yes. While lead spacing differences are minimal (0.201" vs. 0.199"), length and width variations may affect component placement in densely populated boards. Verify PCB footprint specifications and assembly equipment capabilities before substituting parts with different physical dimensions.

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