Part A
0451003.MRL
Công ty Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 7735 PCS
- Series
- Fuses
Replacement verdict
Compatible functional replacement candidate
The 0451002.MRL and 0451003.MRL are both surface-mount slow-blow ceramic fuses from the same Littelfuse 451 series, sharing identical package, voltage rating, and operating temperature range. The only meaningful difference is the current rating, making the 0451003.MRL a viable higher-current alternative where the circuit design permits.
Current Rating
Validation required
Voltage Rating
High match
Package Type
High match
Operating Temperature
High match
Parts at a glance
Part B
0451002.MRL
Công ty Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 4049 PCS
- Package
- 2-SMD
- Series
- Fuses
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 0451002.MRL | 0451003.MRL | Why it matters |
|---|---|---|---|
| Current Rating | 2 A | 3 A | Determines the maximum continuous current the fuse can carry without opening; a direct functional difference affecting circuit protection level. |
| Melting I²t | 1.6 A²s | 4.4 A²s | Indicates the energy required to open the fuse; affects response time under fault currents and coordination with downstream components. |
| Nominal Cold Resistance | 0.0455 Ohm | 0.0285 Ohm | Lower resistance reduces voltage drop and power loss; impacts circuit efficiency and thermal behavior. |
| Voltage Drop at Rated Current | 0.091 V | 0.0855 V | Affects the voltage available to the load and overall circuit performance; a key indicator of insertion loss. |
| Voltage Rating | 125 V AC / 125 V DC | 125 V AC / 125 V DC | Defines the maximum voltage the fuse can safely interrupt; must meet or exceed the application voltage. |
| Interrupting Rating | 50 A at 125 V AC / 300 A at 125 V DC | 50 A at 125 V AC / 300 A at 125 V DC | Specifies the maximum fault current the fuse can safely break without damage or hazard. |
| Fuse Type | Fast-Acting | Fast-Acting | Determines response speed to overcurrent events; fast-acting is suitable for sensitive electronics protection. |
| Package / Size | 1206 (3216 Metric) | 1206 (3216 Metric) | Ensures physical compatibility with the PCB footprint and assembly process. |
| Operating Temperature Range | -55°C to +125°C | -55°C to +125°C | Defines the environmental conditions under which the fuse maintains reliable performance. |
| Approvals / Certifications | UL Recognized, CSA Certified | UL Recognized, CSA Certified | Indicates compliance with safety standards required for end-product certification. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 0451003.MRL | 0451002.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 | 2 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 | 0.53 |
| 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 0451002.MRL and 0451003.MRL fuses?
The 0451002.MRL and 0451003.MRL are Littelfuse Nano2 SMF series surface-mount fuses. The 0451002.MRL is rated 2 A and the 0451003.MRL is rated 3 A, both in a 2410 (6125 metric) package with a 125 V AC / 125 V DC voltage rating and a 50 A interrupting rating.
What is the main difference between the 0451002.MRL and 0451003.MRL?
The primary difference is the current rating: the 0451002.MRL is rated for 2 A and the 0451003.MRL is rated for 3 A. Both share the same Nano2 SMF fuse family, 2410 surface-mount package, 125 V AC / 125 V DC voltage rating, and 50 A interrupting rating.
Are the 0451002.MRL and 0451003.MRL interchangeable in a circuit?
No. Although they share the same package and voltage rating, their current ratings differ (2 A vs. 3 A). Substitution must be evaluated against the circuit's normal operating current, inrush profile, and required overcurrent protection level using the Littelfuse datasheet.
What is the voltage rating of the 0451002.MRL and 0451003.MRL?
Both the 0451002.MRL and 0451003.MRL are rated for 125 V AC and 125 V DC, as specified in the Littelfuse Nano2 SMF series datasheet.
What is the interrupting rating of the 0451002.MRL and 0451003.MRL?
Both fuses have an interrupting rating of 50 A at 125 V AC and 50 A at 125 V DC, per the Littelfuse Nano2 SMF series specifications.
What package and mounting type do the 0451002.MRL and 0451003.MRL use?
Both the 0451002.MRL and 0451003.MRL use the Littelfuse Nano2 SMF surface-mount package in a 2410 (6125 metric) footprint, suitable for automated PCB assembly.
Do the 0451002.MRL and 0451003.MRL have the same breaking capacity and time-current characteristics?
They share the same interrupting rating of 50 A at 125 V AC / 125 V DC and belong to the same Littelfuse Nano2 SMF series, so their time-current curve family is the same. However, the 2 A and 3 A ratings correspond to different points on that curve, so actual clearing times at a given fault current differ.
Which applications are suitable for the 0451002.MRL versus the 0451003.MRL?
Selection depends on the circuit's steady-state current and required protection threshold. The 0451002.MRL (2 A) is used where normal operating current is below 2 A, while the 0451003.MRL (3 A) is used where normal operating current is below 3 A. Both are applicable in 125 V AC / 125 V DC circuits requiring a 50 A interrupting rating, subject to Littelfuse derating and application guidelines.