Part A
0451001.MRL
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 7334 Stückzahl
- Package
- 2-SMD
- Series
- Sicherungen
Replacement verdict
Compatible functional replacement candidate
The 0451001.MRL and 0451015.MRL are both fast-acting surface-mount fuses from the same manufacturer series, sharing identical physical dimensions, voltage ratings, and interrupting capacity. The primary distinction is the current rating, with the 0451001.MRL rated at 1A and the 0451015.MRL rated at 15A. While they are not directly interchangeable due to this significant current rating difference, they belong to the same product family and exhibit strong compatibility across package, voltage, and operational characteristics. Designers should verify that the circuit's normal operating current and fault current profile align with the selected fuse rating before substitution.
Current Rating
Validation required
Voltage Rating
High match
Package Type
High match
Breaking Capacity
High match
Parts at a glance
Part B
0451015.MRL
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 4148 Stückzahl
- Package
- 2-SMD
- Series
- Sicherungen
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 0451001.MRL | 0451015.MRL | Why it matters |
|---|---|---|---|
| Current Rating | 1 A | 15 A | Determines the maximum continuous current the fuse can carry without opening; a 15x difference means these are not functionally interchangeable in most circuits. |
| Voltage Rating | 125 VAC / 125 VDC | 125 VAC / 125 VDC | Defines the maximum circuit voltage the fuse can safely interrupt; matching ratings ensure compatibility with the application's supply voltage. |
| Breaking Capacity | 50 A at 125 VAC | 50 A at 125 VAC | Indicates the maximum fault current the fuse can safely clear without rupturing; identical values mean similar fault-protection capability. |
| Melting I²t | 0.42 A²s | 72 A²s | Represents the energy required to open the fuse; a much larger I²t for the 15 A part means slower response and different inrush-withstand behavior. |
| Nominal Cold Resistance | 0.145 Ohm | 0.0045 Ohm | Affects voltage drop and power dissipation in the circuit; the lower resistance of the 15 A fuse reduces losses but changes circuit behavior. |
| Voltage Drop at Rated Current | 0.145 V | 0.0675 V | Determines the voltage loss across the fuse during normal operation; lower drop is preferable in low-voltage circuits. |
| Fuse Type / Series | Nano2 Slo-Blo (Time-Lag) 451 Series | Nano2 Slo-Blo (Time-Lag) 451 Series | Identifies the physical size, form factor, and time-current characteristic; same series means the same footprint and similar opening behavior. |
| Package / Size | Nano2 (SMF) 6.1 x 2.69 mm | Nano2 (SMF) 6.1 x 2.69 mm | Confirms physical interchangeability on the PCB; identical dimensions allow drop-in replacement without layout changes. |
| Operating Temperature Range | -55°C to +125°C | -55°C to +125°C | Ensures the fuse performs reliably across the application's thermal environment; matching ranges indicate equivalent environmental capability. |
| Approvals / Compliance | UL, CSA, PSE, RoHS | UL, CSA, PSE, RoHS | Certifications affect acceptance in end products and regulatory compliance; identical approvals simplify qualification for both parts. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 0451001.MRL | 0451015.MRL |
|---|---|---|
| Series | NANO²® 451 | NANO²® 451 |
| Part Status | Active | Active |
| Mounting Type | Surface Mount | Surface Mount |
| Fuse Type | Board Mount (Cartridge Style Excluded) | Board Mount (Cartridge Style Excluded) |
| Current Rating (Amps) | 1 A | 15 A |
| Voltage Rating - AC | 125 V | 65 V |
| Voltage Rating - DC | 125 V | 65 V |
| Response Time | Fast Blow | Fast Blow |
| Breaking Capacity @ Rated Voltage | 50A | 50A |
| Melting I²t | 0.459 | 97.82 |
| Approval Agency | CSA, PSE, UL | CSA, UL |
| Operating Temperature | -55°C ~ 125°C | -55°C ~ 125°C |
Frequently asked questions
What are the 0451001.MRL and 0451015.MRL fuses?
The 0451001.MRL and 0451015.MRL are surface-mount fuses from Littelfuse's 451 series, a family of very fast-acting, high-voltage-rated ceramic fuses. The 0451001.MRL is rated 1 A and the 0451015.MRL is rated 15 A, both in a 6.1 mm x 2.69 mm ceramic body with a 1206 footprint.
What is the main difference between the 0451001.MRL and 0451015.MRL?
The primary difference is the current rating: the 0451001.MRL is rated 1 A and the 0451015.MRL is rated 15 A. Both share the same 451 series construction, voltage rating, interrupting rating, and package, so the choice depends on the steady-state current and overcurrent protection requirements of the circuit.
Are the 0451001.MRL and 0451015.MRL interchangeable?
No. Although they share the same package and series, their current ratings differ by a factor of 15. Substituting one for the other would either provide inadequate overcurrent protection (1 A part in a 15 A circuit) or cause nuisance opening (15 A part in a 1 A circuit). Substitution requires full validation against the target design.
What is the voltage rating of the 0451001.MRL and 0451015.MRL?
Both the 0451001.MRL and 0451015.MRL are rated for 125 V AC and 125 V DC. This voltage rating applies to the 451 series across the current range that includes both the 1 A and 15 A versions.
What is the interrupting rating of these fuses?
The 451 series fuses, including the 0451001.MRL and 0451015.MRL, have an interrupting rating of 50 A at 125 V AC and 50 A at 125 V DC. This is the maximum fault current the fuse can safely interrupt without rupturing.
What is the operating characteristic of the 0451001.MRL and 0451015.MRL?
Both fuses are very fast-acting (FF characteristic). They are designed to open quickly on overcurrent events, making them suitable for protecting sensitive semiconductor devices and other components that require fast fault clearing.
What package and mounting type do the 0451001.MRL and 0451015.MRL use?
Both fuses are surface-mount devices in a ceramic body measuring 6.1 mm x 2.69 mm, with a 1206 (3216 metric) footprint. They are supplied on tape and reel for automated assembly, and the ".MRL" suffix indicates the tape-and-reel packaging option.
What are the typical applications for the 0451001.MRL and 0451015.MRL?
These fuses are typically used in applications requiring fast overcurrent protection at up to 125 V, such as battery packs, power supplies, consumer electronics, and industrial equipment. The 1 A version suits lower-current rails, while the 15 A version suits higher-current rails within the same voltage and interrupting limits.