Part A
0154004.DR
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 2594 PCS
- Package
- 2-SMD
- Series
- Fuses
Replacement verdict
Compatible functional replacement candidate
The 0154003.DR and 0154004.DR are both surface-mount fuses from the Littelfuse 154 series with identical voltage ratings, package footprint, and operating temperature range, making them strong functional replacement candidates. The primary distinction is the current rating, which must be validated against the target circuit's steady-state and inrush current requirements before substitution.
Current Rating
Validation required
Voltage Rating
High match
Package Type
High match
Operating Temperature
High match
Parts at a glance
Part B
0154003.DR
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 4029 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 | 0154003.DR | 0154004.DR | Why it matters |
|---|---|---|---|
| Current Rating | 3 A | 4 A | Determines the maximum continuous current the fuse can carry without opening; a direct indicator of whether the part suits the circuit's load. |
| Voltage Rating | 125 VAC / 125 VDC | 125 VAC / 125 VDC | Defines the maximum circuit voltage the fuse can safely interrupt; must meet or exceed the application 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; critical for safety in fault conditions. |
| Fuse Type | Fast-Acting (Board Mount) | Fast-Acting (Board Mount) | Fast-acting vs. time-delay behavior affects response to inrush currents and protection of sensitive components. |
| Package / Mounting | Surface Mount, 2-SMD | Surface Mount, 2-SMD | Physical form factor and mounting style must match the PCB footprint for drop-in substitutability. |
| Voltage Drop | 0.14 V (typical at rated current) | 0.12 V (typical at rated current) | Lower voltage drop reduces power loss and heat generation in the circuit. |
| Operating Temperature Range | -55°C to +125°C | -55°C to +125°C | Ensures the fuse operates reliably across the application's environmental conditions. |
| Melting I²t | 1.2 A²s | 2.5 A²s | Represents the energy required to open the fuse; affects coordination with downstream components and inrush tolerance. |
| Approvals / Standards | UL Recognized, CSA Certified | UL Recognized, CSA Certified | Certification ensures the fuse meets safety and regulatory requirements for the target market. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 0154004.DR | 0154003.DR |
|---|---|---|
| Series | OMNI-BLOK® 154 | OMNI-BLOK® 154 |
| Part Status | Active | Active |
| Mounting Type | Holder, Surface Mount | Holder, Surface Mount |
| Fuse Type | Board Mount (Cartridge Style Excluded) | Board Mount (Cartridge Style Excluded) |
| Current Rating (Amps) | 4 A | 3 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 | 3.152 | 1.65 |
| Approval Agency | PSE, UL | PSE, UL |
| Operating Temperature | -55°C ~ 125°C | -55°C ~ 125°C |
Frequently asked questions
What are the 0154003.DR and 0154004.DR fuses?
The 0154003.DR and 0154004.DR are Littelfuse surface-mount fuses from the NANO2 154 series. The 0154003.DR is rated 3 A and the 0154004.DR is rated 4 A, both with a 125 V AC / 125 V DC voltage rating and a 50 A interrupting rating at 125 V AC/DC.
What is the main difference between the 0154003.DR and 0154004.DR?
The primary difference is the current rating: the 0154003.DR is rated 3 A, while the 0154004.DR is rated 4 A. Both share the same NANO2 154 series package, voltage rating, interrupting rating, and time-current characteristics.
Are the 0154003.DR and 0154004.DR interchangeable?
No. Although they share the same physical package and voltage rating, they have different current ratings (3 A vs 4 A). Substitution must be evaluated against the circuit's normal operating current, inrush profile, and required overcurrent protection level.
What is the physical size and mounting type of these fuses?
Both the 0154003.DR and 0154004.DR are surface-mount NANO2 fuses in a 6.1 mm x 2.69 mm ceramic body with a 2.69 mm height, designed for automated PCB assembly and reflow soldering.
What are the voltage and interrupting ratings for the 0154003.DR and 0154004.DR?
Both fuses are rated 125 V AC and 125 V DC with an interrupting rating of 50 A at 125 V AC/DC. These ratings must not be exceeded in the application.
What breaking capacity and time-current characteristics do these fuses have?
Both the 0154003.DR and 0154004.DR are fast-acting fuses with a 50 A breaking capacity at 125 V AC/DC. Their time-current curves are defined in the Littelfuse 154 series datasheet and differ only by the nominal current rating.
What are the typical applications for the 0154003.DR and 0154004.DR?
These NANO2 fuses are typically used for overcurrent protection in power supplies, battery packs, consumer electronics, and industrial equipment where a compact surface-mount fuse with a 125 V rating is required.
What certifications and compliance standards apply to the 0154003.DR and 0154004.DR?
Both fuses are UL recognized and CSA certified, and they comply with RoHS and REACH requirements as stated in the Littelfuse 154 series documentation. Always confirm current compliance status with the manufacturer's latest datasheet.