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PFRA.300 Polymeric PTC Resettable Fuse 30V 3A Radial
Part Overview
The PFRA.300 is a polymeric PTC resettable fuse manufactured by SCHURTER Inc., designed for through-hole radial mounting in 30V circuits with a 3A hold current rating. This component provides automatic overcurrent protection with the ability to reset after a fault condition is cleared. The part is active in production and ROHS3 compliant, making it suitable for modern electronic applications requiring circuit protection without permanent component replacement.
Alternative models become necessary when design requirements specify different current ratings, packaging formats, or when preferred manufacturers are unavailable. Substitute parts must maintain electrical compatibility across voltage, hold current, and trip current parameters while accommodating mechanical constraints of the application.
Substiute Parts
Key Parameters
| Parameter | Value |
|---|---|
| Voltage - Max | 30V |
| Current - Hold (Ih) (Max) | 3 A |
| Current - Trip (It) | 6 A |
| Current - Max | 40 A |
| Time to Trip | 10.8 s |
| Resistance - Initial (Ri) (Min) | 20 mOhms |
| Resistance - Post Trip (R1) (Max) | 80 mOhms |
| Operating Temperature | -40°C ~ 85°C |
| Mounting Type | Through Hole |
| Package / Case | Radial, Disc |
| Lead Spacing | 0.201" (5.10mm) |
| Approval Agency | cURus, TUV |
| RoHS Status | ROHS3 Compliant |
Substitute Part Grouping Explanation
Substitution of the PFRA.300 is determined by strict electrical and mechanical compatibility criteria. The primary substitution constraint is the Current - Hold (Ih) rating of 3A, which defines the maximum continuous current the fuse permits without tripping. The Voltage - Max of 30V establishes the upper voltage limit for circuit application. The Current - Trip (It) of 6A defines the threshold at which the fuse transitions to high-resistance state.
Secondary compatibility factors include lead spacing (0.201" / 5.10mm), mounting type (through hole radial), and package form (radial disc). These mechanical parameters ensure physical fit within the PCB footprint. Resistance characteristics (Ri and R1) and time-to-trip specifications must align with circuit protection requirements.
Direct substitutes maintain identical or equivalent Current - Hold, Voltage - Max, Current - Trip, and lead spacing values. Parts with different current ratings (4A, 5A, 6A, 7A, 8A, 9A) are classified as similar alternatives suitable only when circuit design permits higher hold current thresholds.
Parameter Comparison
| Part Number | Manufacturer | Voltage - Max | Current - Hold (Ih) (Max) | Current - Trip (It) | Resistance - Initial (Ri) (Min) | Resistance - Post Trip (R1) (Max) | Time to Trip | Lead Spacing | Packaging | RoHS Status |
|---|---|---|---|---|---|---|---|---|---|---|
| PFRA.300 | SCHURTER Inc. | 30V | 3 A | 6 A | 20 mOhms | 80 mOhms | 10.8 s | 0.201" (5.10mm) | Bulk | ROHS3 Compliant |
| FRU300-30F | RFE/Fuzetec | 30V | 3 A | 6 A | 20 mOhms | 80 mOhms | 10.8 s | 0.201" (5.10mm) | Bulk | ROHS3 Compliant |
| 0ZRB0300FF1A | Bel Fuse Inc. | 30V | 3 A | 6 A | 20 mOhms | 80 mOhms | 10.8 s | 0.201" (5.10mm) | Box | ROHS3 Compliant |
| 0ZRB0300FF2B | Bel Fuse Inc. | 30V | 3 A | 6 A | 20 mOhms | 80 mOhms | 10.8 s | 0.201" (5.10mm) | Cut Tape (CT) | ROHS3 Compliant |
| 0ZRB0400FF1A | Bel Fuse Inc. | 30V | 4 A | 8 A | 10 mOhms | 50 mOhms | 12.7 s | 0.201" (5.10mm) | Box | ROHS3 Compliant |
| 0ZRB0400FF2B | Bel Fuse Inc. | 30V | 4 A | 8 A | 10 mOhms | 50 mOhms | 12.7 s | 0.201" (5.10mm) | Cut Tape (CT) | ROHS3 Compliant |
| 0ZRB0500FF1A | Bel Fuse Inc. | 30V | 5 A | 10 A | 10 mOhms | 50 mOhms | 14.5 s | 0.402" (10.20mm) | Box | ROHS3 Compliant |
| 0ZRB0600FF1A | Bel Fuse Inc. | 30V | 6 A | 12 A | 5 mOhms | 40 mOhms | 16 s | 0.402" (10.20mm) | Box | ROHS3 Compliant |
| 0ZRB0700FF1A | Bel Fuse Inc. | 30V | 7 A | 14 A | 5 mOhms | 30 mOhms | 17.5 s | 0.402" (10.20mm) | Box | ROHS3 Compliant |
| 0ZRB0800FF1A | Bel Fuse Inc. | 30V | 8 A | 16 A | 5 mOhms | 20 mOhms | 18.8 s | 0.402" (10.20mm) | Box | ROHS3 Compliant |
| 0ZRB0900FF1A | Bel Fuse Inc. | 30V | 9 A | 18 A | 5 mOhms | 20 mOhms | 20 s | 0.402" (10.20mm) | Box | ROHS3 Compliant |
Engineering Selection Recommendations
Direct substitutes for PFRA.300 are FRU300-30F, 0ZRB0300FF1A, and 0ZRB0300FF2B. These parts maintain identical electrical specifications: 30V maximum voltage, 3A hold current, 6A trip current, and 10.8 second time-to-trip. All three alternatives are ROHS3 compliant and carry appropriate regulatory approvals (cURus, TUV, or cUL/TUV/UL). Selection among direct substitutes depends on packaging requirements and inventory availability.
FRU300-30F (RFE/Fuzetec) provides equivalent electrical performance with bulk packaging. The 0ZRB series from Bel Fuse Inc. offers two packaging options: 0ZRB0300FF1A in box format and 0ZRB0300FF2B in cut tape format. Bel Fuse components carry AEC-Q200 automotive qualification, providing additional reliability assurance for applications requiring automotive-grade components.
Higher current-rated alternatives (0ZRB0400FF1A through 0ZRB0900FF1A) are suitable only when circuit design permits increased hold current thresholds. These parts maintain 30V voltage compatibility but feature progressively higher trip currents and modified resistance characteristics. Lead spacing changes from 0.201" to 0.402" for 5A and higher ratings require PCB footprint verification before substitution.
Frequently Asked Questions (FAQ)
Q: Can 0ZRB0400FF1A replace PFRA.300 in my circuit?
A: 0ZRB0400FF1A is not a direct substitute. It features a 4A hold current versus the PFRA.300's 3A rating, meaning it permits higher continuous current before tripping. Substitution is only valid if your circuit design allows this increased threshold. Additionally, the lead spacing differs (0.201" vs. 0.402"), requiring PCB footprint modification.
Q: What is the difference between 0ZRB0300FF1A and 0ZRB0300FF2B?
A: Both parts are electrically identical with matching 30V voltage, 3A hold current, and 6A trip current specifications. The difference is packaging format: 0ZRB0300FF1A is supplied in box packaging, while 0ZRB0300FF2B is supplied in cut tape format. Selection depends on assembly process requirements and inventory management preferences.
Q: Are all substitute parts ROHS3 compliant?
A: Yes. PFRA.300 and all listed substitute parts are ROHS3 compliant, meeting current environmental and hazardous substance restrictions for electronic components.
Q: Does FRU300-30F have automotive qualification?
A: FRU300-30F does not list AEC-Q200 qualification in the provided specifications. If automotive-grade components are required, 0ZRB0300FF1A or 0ZRB0300FF2B from Bel Fuse Inc. carry AEC-Q200 certification.
Q: What regulatory approvals apply to PFRA.300 substitutes?
A: PFRA.300 carries cURus and TUV approvals. FRU300-30F carries cUL, TUV, and UL approvals. Bel Fuse 0ZRB series parts carry cURus and TUV approvals. All approvals are suitable for general industrial and consumer applications within the specified voltage and current parameters.
Q: Can I use a higher current-rated fuse for better reliability?
A: Higher current ratings provide different protection characteristics, not improved reliability. A 4A-rated fuse (0ZRB0400FF1A) will not trip until 8A is reached, versus 6A for the PFRA.300. This changes circuit protection behavior and may allow fault currents to persist longer than the original design intended. Substitution with higher ratings requires circuit analysis to confirm acceptability.
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