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PFLR.730 Polymeric PTC Resettable Fuse 10V 7.3A Equivalent & Substitute Parts
Part Overview
The PFLR.730 is a polymeric PTC resettable fuse manufactured by SCHURTER Inc., rated for 10V maximum voltage with a 7.3A hold current (Ih). This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The PFLR.730 operates across a temperature range of -45°C to 85°C and provides automatic trip protection at 14.1A with a 5-second response time. Substitute parts must maintain electrical equivalence in voltage rating, hold current, and trip characteristics while accommodating available active alternatives from current manufacturers.
Substiute Parts
Key Parameters
| Parameter | PFLR.730 Value |
|---|---|
| Manufacturer | SCHURTER Inc. |
| Voltage - Max | 10V |
| Current - Hold (Ih) (Max) | 7.3 A |
| Current - Trip (It) | 14.1 A |
| Time to Trip | 5 s |
| Resistance - Initial (Ri) (Min) | 6 mOhms |
| Resistance - Post Trip (R1) (Max) | 15 mOhms |
| Operating Temperature | -45°C ~ 85°C |
| Type | Polymeric |
| Package / Case | Strap |
| Product Status | Obsolete |
| RoHS Status | ROHS3 Compliant |
| Approval Agency | CSA, TUV, UL |
Substitute Part Grouping Explanation
Substitute parts for the PFLR.730 are selected based on strict electrical and mechanical equivalence. The primary substitution criterion is matching the 10V voltage rating and 7.3A hold current specification. The PFLR.730 exhibits a trip current of 14.1A with 6 mOhms initial resistance and 15 mOhms maximum post-trip resistance.
The direct electrical equivalent is the MF-LR730 from Bourns Inc., which maintains identical voltage, hold current, trip current, and resistance characteristics. This part is currently active and available in production quantities.
Secondary substitutes include the MF-LR600 (6A hold current) and MF-LR550 (5.5A hold current), which provide lower hold current ratings suitable for applications requiring reduced trip thresholds. These parts maintain the 10V voltage rating and 5-second trip time but differ in current-handling capacity and resistance profiles.
The MF-SVS series parts (MF-SVS170-0, MF-SVS175-0, MF-SVS210-0 and variants) represent lower current-rated alternatives with significantly different electrical characteristics and are suitable only for applications with substantially lower current requirements.
Parameter Comparison
| Parameter | PFLR.730 | MF-LR730 | MF-LR600 | MF-LR550 | MF-SVS210-0 | MF-SVS175-0 |
|---|---|---|---|---|---|---|
| Manufacturer | SCHURTER Inc. | Bourns Inc. | Bourns Inc. | Bourns Inc. | Bourns Inc. | Bourns Inc. |
| Voltage - Max | 10V | 10V | 10V | 10V | 10V | 10V |
| Current - Hold (Ih) (Max) | 7.3 A | 7.3 A | 6 A | 5.5 A | 2.1 A | 1.75 A |
| Current - Trip (It) | 14.1 A | 14.1 A | 11.7 A | 10.5 A | 5 A | 4.2 A |
| Time to Trip | 5 s | 5 s | 5 s | 5 s | 5 s | 5 s |
| Resistance - Initial (Ri) (Min) | 6 mOhms | 6 mOhms | 7 mOhms | 9 mOhms | 10 mOhms | 17 mOhms |
| Resistance - Post Trip (R1) (Max) | 15 mOhms | 15 mOhms | 19 mOhms | 22 mOhms | 40 mOhms | 63 mOhms |
| Operating Temperature | -45°C ~ 85°C | -40°C ~ 85°C | -40°C ~ 85°C | -40°C ~ 85°C | -40°C ~ 85°C | -40°C ~ 85°C |
| Type | Polymeric | Polymeric | Polymeric | Polymeric | Polymeric | Polymeric |
| Package / Case | Strap | Strap | Strap | Strap | Strap | Strap |
| Product Status | Obsolete | Active | Active | Active | Active | Active |
| RoHS Status | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant |
| Approval Agency | CSA, TUV, UL | cURus, TUV | cURus, TUV | cURus, TUV | cURus, TUV | cURus, TUV |
Engineering Selection Recommendations
The MF-LR730 from Bourns Inc. is the primary substitute for the PFLR.730. This part maintains complete electrical equivalence with identical voltage rating (10V), hold current (7.3A), trip current (14.1A), and resistance characteristics (6 mOhms initial, 15 mOhms post-trip maximum). The MF-LR730 is currently in active production status with cURus and TUV certifications and ROHS3 compliance, ensuring long-term availability and regulatory alignment.
The MF-LR600 and MF-LR550 are suitable alternatives only for applications where reduced hold current thresholds are acceptable. These parts maintain 10V voltage rating and 5-second trip time but provide lower current capacity and higher post-trip resistance values.
The MF-SVS series parts are not recommended as direct substitutes due to significantly lower current ratings (1.7A to 2.1A hold current) and substantially higher resistance values. These parts are suitable only for distinctly different circuit protection requirements.
All recommended substitutes maintain ROHS3 compliance and operate across the -40°C to 85°C temperature range. The PFLR.730 operates to -45°C minimum; applications requiring operation below -40°C must retain the original PFLR.730 or identify alternative solutions.
Frequently Asked Questions (FAQ)
Q: Can the MF-LR730 directly replace the PFLR.730 in existing designs?
A: Yes. The MF-LR730 provides complete electrical equivalence in voltage rating, hold current, trip current, and resistance characteristics. Both parts are polymeric PTC resettable fuses in strap package configuration. Mechanical dimensions differ slightly (PFLR.730: 27.55mm × 14.20mm; MF-LR730: 29.55mm × 14.45mm), requiring verification of board layout clearance.
Q: What is the difference between hold current (Ih) and trip current (It)?
A: Hold current (Ih) is the maximum continuous current the fuse conducts without tripping. Trip current (It) is the threshold at which the fuse activates protection. The PFLR.730 holds 7.3A continuously and trips at 14.1A. Substitute parts with lower Ih ratings will trip at lower current thresholds.
Q: Are the MF-SVS series parts suitable substitutes?
A: No. The MF-SVS series parts (1.7A to 2.1A hold current) are designed for distinctly different applications requiring lower current protection. These parts are not electrically equivalent to the PFLR.730 and will not provide equivalent circuit protection.
Q: What certifications apply to substitute parts?
A: The MF-LR730 carries cURus and TUV certifications. The original PFLR.730 carries CSA, TUV, and UL certifications. Applications requiring UL certification must confirm whether cURus certification meets regulatory requirements for the specific end application.
Q: Does operating temperature range affect substitution?
A: The PFLR.730 operates from -45°C to 85°C. The MF-LR730 operates from -40°C to 85°C. Applications requiring operation below -40°C cannot use the MF-LR730 as a substitute.
Q: What is the significance of initial resistance (Ri) and post-trip resistance (R1)?
A: Initial resistance (Ri) represents the fuse's resistance during normal operation and affects circuit performance and power dissipation. Post-trip resistance (R1) is the resistance after the fuse has tripped and is in protection mode. The PFLR.730 exhibits 6 mOhms initial and 15 mOhms maximum post-trip resistance. Substitute parts with higher resistance values will exhibit increased voltage drop and power dissipation.
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