Part A
1812L110/33MR
Littelfuse sa.
- Lifecycle
- Active
- Stock
- 5657 PCS
- Package
- 1812 (4532 Metric), Concave
- Series
- Fusible réinitialisable PTC
Replacement verdict
Not a drop-in replacement
The 1812L014DR and 1812L110/33MR are both 1812-package PPTC resettable fuses, but they are not functionally interchangeable. The 1812L014DR is a low-hold-current device intended for sensitive, low-power circuit protection, while the 1812L110/33MR is a high-current, high-voltage-rated device designed for substantially higher fault-energy environments. Their divergent hold current, trip current, voltage rating, and time-to-trip characteristics make direct substitution inadvisable without a full circuit re-evaluation.
Different hold current
Different voltage rating
Different trip characteristics
Different power dissipation
Parts at a glance
Part B
1812L014DR
Littelfuse sa.
- Lifecycle
- Active
- Stock
- 6803 PCS
- Package
- 1812 (4532 Metric), Concave
- Series
- Fusible réinitialisable PTC
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 1812L014DR | 1812L110/33MR | Why it matters |
|---|---|---|---|
| Hold Current (Ih) | 0.14 A | 1.10 A | Defines the maximum continuous current the device passes without tripping; a higher hold current allows more load current before protection activates. |
| Trip Current (It) | 0.34 A | 2.20 A | The minimum current guaranteed to trip the device; it sets the threshold above which overcurrent protection reliably engages. |
| Maximum Voltage Rating | 60 V | 33 V | The highest voltage the device can withstand while tripped; it must exceed the circuit's maximum operating voltage for safe protection. |
| Maximum Interrupt Current | 10 A | 40 A | The largest fault current the device can safely interrupt; higher ratings provide robustness against severe short-circuit events. |
| Initial Resistance (Rmin) | 1.5 Ω | 0.06 Ω | Lower resistance reduces voltage drop and power loss in normal operation, which is critical for higher-current circuits. |
| Post-Trip Resistance (R1max) | 6.0 Ω | 0.20 Ω | Maximum resistance after tripping affects residual voltage drop and heat generation once the device resets. |
| Time to Trip at Rated Current | 0.15 s | 0.50 s | Response speed determines how quickly the device protects downstream components during an overcurrent event. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Defines the ambient conditions under which the device maintains its specified electrical characteristics. |
| Package / Size | 1812 (4532 metric) | 1812 (4532 metric) | Physical footprint must match the PCB land pattern for direct drop-in substitution. |
| Mounting Type | Surface Mount | Surface Mount | Assembly method must be compatible with the manufacturing process and board design. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 1812L110/33MR | 1812L014DR |
|---|---|---|
| Series | POLY-FUSE®, 1812L | POLY-FUSE®, 1812L |
| Part Status | Active | Active |
| Type | Polymeric | Polymeric |
| Voltage - Max | 33V | 60V |
| Current - Max | 20 A | 10 A |
| Current - Hold(Ih)(Max) | 1.1 A | 140 mA |
| Current - Trip(It) | 1.95 A | 340 mA |
| Timeto Trip | 500 ms | 150 ms |
| Resistance - Initial(Ri)(Min) | 60 mOhms | 1.5 Ohms |
| Resistance - Post Trip(R1)(Max) | 200 mOhms | 6 Ohms |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Size / Dimension | 0.179 L x 0.128 W (4.55mm x 3.24mm) | 0.179 L x 0.128 W (4.55mm x 3.24mm) |
| Thickness(Max) | 0.079 (2.00mm) | 0.077 (1.95mm) |
Frequently asked questions
What are the key differences between the 1812L014DR and the 1812L110/33MR PTC resettable fuses?
The 1812L014DR is a 1812-size polyfuse with a hold current of 0.14 A and a maximum voltage rating of 60 V, while the 1812L110/33MR is a 1812-size polyfuse with a hold current of 1.10 A and a maximum voltage rating of 33 V. The 1812L014DR is designed for lower-current, higher-voltage circuits, whereas the 1812L110/33MR is designed for higher-current, lower-voltage circuits.
Are the 1812L014DR and 1812L110/33MR interchangeable in a circuit?
No, they are not directly interchangeable. The 1812L014DR has a hold current of 0.14 A and a trip current of 0.28 A, while the 1812L110/33MR has a hold current of 1.10 A and a trip current of 2.20 A. Substituting one for the other would result in incorrect overcurrent protection and potential circuit malfunction or damage.
What is the maximum voltage rating for each device?
The 1812L014DR has a maximum voltage rating of 60 V, and the 1812L110/33MR has a maximum voltage rating of 33 V. These ratings must not be exceeded in the application.
What are the hold and trip currents for the 1812L014DR?
The 1812L014DR has a hold current of 0.14 A at 20°C and a trip current of 0.28 A at 20°C, with a maximum time-to-trip of 0.15 s at 0.70 A.
What are the hold and trip currents for the 1812L110/33MR?
The 1812L110/33MR has a hold current of 1.10 A at 20°C and a trip current of 2.20 A at 20°C, with a maximum time-to-trip of 0.50 s at 5.50 A.
Do both devices have the same physical footprint and package?
Yes, both the 1812L014DR and the 1812L110/33MR are supplied in the 1812 (4532 metric) surface-mount package, with compatible pad layouts and dimensions as specified in their respective datasheets.
What are the typical applications for each fuse?
The 1812L014DR is typically used in low-current, higher-voltage circuits such as industrial control, telecommunications, and battery chargers. The 1812L110/33MR is typically used in higher-current, lower-voltage circuits such as USB peripherals, portable electronics, and power supplies.
What is the operating temperature range for these PTC resettable fuses?
Both the 1812L014DR and the 1812L110/33MR are rated for an operating temperature range of -40°C to +85°C, as specified in their manufacturer datasheets.