Part A
0451003.MRL
Компания Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 7735 ПКС
- Series
- Защитники
Replacement verdict
Compatible functional replacement candidate
The 0451003.MRL and 0451007.MRL are both fast-acting surface-mount fuses from the Littelfuse 451 series, sharing identical physical dimensions, voltage ratings, and interrupting capacity. The primary distinction is the current rating, making the 0451007.MRL a viable higher-current alternative to the 0451003.MRL in circuits designed to accommodate the increased amperage. Designers must verify that the higher current rating aligns with their overcurrent protection requirements before substituting.
Current Rating
Validation required
Voltage Rating
High match
Package Type
High match
Breaking Capacity
High match
Parts at a glance
Part B
0451007.MRL
Компания Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 4553 ПКС
- Package
- 2-SMD
- Series
- Защитники
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 0451003.MRL | 0451007.MRL | Why it matters |
|---|---|---|---|
| Current Rating | 3 A | 7 A | Determines the maximum continuous current the fuse can carry without opening; a direct functional substitutability constraint. |
| Voltage Rating (DC) | 125 V | 125 V | Defines the maximum DC voltage the fuse can safely interrupt; must meet or exceed the circuit voltage. |
| Voltage Rating (AC) | 125 V | 125 V | Defines the maximum AC voltage the fuse can safely interrupt; must meet or exceed the circuit voltage. |
| Interrupting Rating | 50 A @ 125 VAC / 50 A @ 125 VDC | 50 A @ 125 VAC / 50 A @ 125 VDC | Indicates the maximum fault current the fuse can safely clear without rupturing; critical for safety compliance. |
| Nominal Melting I²t | 4.4 A²s | 26.5 A²s | Represents the energy required to open the fuse; affects coordination with downstream components and inrush tolerance. |
| Nominal Voltage Drop | 0.14 V | 0.11 V | Lower voltage drop reduces power loss and heat generation in the circuit. |
| Nominal Cold Resistance | 0.0465 Ohm | 0.0155 Ohm | Affects circuit impedance and voltage drop; lower resistance is generally preferred for efficiency. |
| Fuse Type | Fast-Acting (Nano²) | Fast-Acting (Nano²) | Determines the time-current response; fast-acting fuses protect sensitive components from rapid overcurrent events. |
| Package / Size | Nano² SMF (6.10 mm x 2.69 mm) | Nano² SMF (6.10 mm x 2.69 mm) | Physical footprint and mounting style must match the PCB layout for drop-in substitutability. |
| Operating Temperature Range | -55°C to +125°C | -55°C to +125°C | Ensures reliable operation and proper derating across the application's environmental conditions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 0451003.MRL | 0451007.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) | 3 A | 7 A |
| Voltage Rating - AC | 125 V | 125 V |
| Voltage Rating - DC | 125 V | 125 V |
| Response Time | Fast Blow | Fast Blow |
| Breaking Capacity @ Rated Voltage | 50A | 50A |
| Melting I²t | 1.65 | 10.32 |
| Approval Agency | CSA, PSE, UL | CSA, PSE, UL |
| Operating Temperature | -55°C ~ 125°C | -55°C ~ 125°C |
| Size / Dimension | 0.240" L x 0.106" W x 0.106" H (6.10mm x 2.69mm x 2.69mm) | - |
| Packaging | Cut Tape (CT), Tape & Reel (TR) | - |
Frequently asked questions
What are the 0451003.MRL and 0451007.MRL fuses?
The 0451003.MRL and 0451007.MRL are surface-mount fuses from Littelfuse's 451 series, designed for overcurrent protection in electronic circuits. The 0451003.MRL has a rated current of 3 A, while the 0451007.MRL has a rated current of 7 A, both with a voltage rating of 125 VAC/VDC.
What is the main difference between the 0451003.MRL and 0451007.MRL?
The primary difference is the current rating: the 0451003.MRL is rated for 3 A, and the 0451007.MRL is rated for 7 A. Both share the same voltage rating, breaking capacity, and physical package, making them suitable for different current protection levels in similar circuit designs.
Are the 0451003.MRL and 0451007.MRL interchangeable in a circuit?
No, they are not directly interchangeable because their current ratings differ. Substituting a 3 A fuse with a 7 A fuse (or vice versa) can compromise circuit protection. Always match the fuse rating to the design requirements specified by the manufacturer or circuit designer.
What is the voltage rating of the 0451003.MRL and 0451007.MRL?
Both the 0451003.MRL and 0451007.MRL have a voltage rating of 125 VAC/VDC, as specified in the Littelfuse 451 series datasheet. This rating indicates the maximum voltage the fuse can safely interrupt under fault conditions.
What is the breaking capacity of the 0451003.MRL and 0451007.MRL?
Both fuses have a breaking capacity of 50 A at 125 VAC/VDC, according to the Littelfuse 451 series datasheet. This is the maximum fault current the fuse can safely interrupt without damage or hazardous failure.
What package type do the 0451003.MRL and 0451007.MRL use?
Both the 0451003.MRL and 0451007.MRL are housed in a surface-mount package with a footprint of 6.1 mm x 2.5 mm (0.240 in x 0.098 in) and a height of 2.5 mm (0.098 in), as per the Littelfuse 451 series datasheet. They are designed for automated PCB assembly.
What are the typical applications for the 0451003.MRL and 0451007.MRL?
These fuses are commonly used in consumer electronics, power supplies, battery chargers, and industrial equipment for overcurrent protection. The 0451003.MRL suits lower-current circuits, while the 0451007.MRL is used in higher-current applications, as indicated by their respective ratings.
Do the 0451003.MRL and 0451007.MRL have the same time-current characteristics?
Yes, both fuses belong to the same Littelfuse 451 series and share similar time-current characteristics, typically fast-acting. However, the actual melting time at a given overcurrent will differ due to their different current ratings, as shown in the series datasheet.
Are the 0451003.MRL and 0451007.MRL RoHS compliant?
Yes, both the 0451003.MRL and 0451007.MRL are RoHS compliant and lead-free, as stated in the Littelfuse 451 series datasheet and product specifications. This makes them suitable for use in environmentally sensitive applications.