Part A
2920L185DR
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 5519 PCS
- Package
- 2920 (7351 Metric), Concave
- Series
- PTC Fuses Resetáveis
Replacement verdict
Not a drop-in replacement
The 2920L075/60MR and 2920L185DR are both 2920-size PPTC resettable fuses, but they differ substantially in hold current, trip current, and voltage rating, making them unsuitable as direct substitutes in the same circuit position. The 2920L075/60MR is rated for higher voltage and lower current, while the 2920L185DR supports higher current at a lower voltage, so the two parts serve different protection requirements and cannot be interchanged without redesign validation.
Different hold current
Different trip current
Different voltage rating
Different time-to-trip
Parts at a glance
Part B
2920L075/60MR
Littelfuse Inc.
- Lifecycle
- Active
- Stock
- 4392 PCS
- Package
- 2920 (7351 Metric), Concave
- Series
- PTC Fuses Resetáveis
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | 2920L075/60MR | 2920L185DR | Why it matters |
|---|---|---|---|
| Hold Current (Ih) | 0.75 A | 1.85 A | Defines the maximum continuous current the device passes without tripping; a higher hold current allows the circuit to operate at higher steady-state loads. |
| Trip Current (It) | 1.5 A | 3.7 A | The minimum current at which the device is guaranteed to trip; it sets the fault-current threshold for protection. |
| Maximum Voltage Rating | 60 V | 33 V | Determines the highest circuit voltage the device can safely interrupt; exceeding it risks device failure or unsafe operation. |
| Initial Resistance (Rmin) | 0.30 Ω | 0.040 Ω | Lower resistance reduces voltage drop and power loss in normal operation, which is critical for low-voltage or power-sensitive circuits. |
| Maximum Resistance (R1max) | 1.20 Ω | 0.150 Ω | Represents the worst-case resistance after tripping; it affects the residual voltage drop and heat generation in the protected circuit. |
| Maximum Time to Trip | 1.5 s at 3.75 A | 2.5 s at 9.25 A | Indicates how quickly the device protects the circuit under a specified fault current; faster trip times limit stress on downstream components. |
| Maximum Power Dissipation | 1.5 W | 1.9 W | Sets the thermal limit the device can handle in the tripped state; higher dissipation capability supports higher-energy fault conditions. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Defines the ambient temperature range over which the device maintains its specified electrical characteristics. |
| Package / Footprint | 2920 (7351 metric) | 2920 (7351 metric) | Physical size and pad layout determine whether the parts are drop-in compatible on the same PCB footprint. |
| Mounting Type | Surface Mount | Surface Mount | Confirms the assembly method; both must match the board's mounting process for direct substitution. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | 2920L185DR | 2920L075/60MR |
|---|---|---|
| Series | POLY-FUSE®, 2920L | POLY-FUSE®, 2920L |
| Part Status | Active | Active |
| Type | Polymeric | Polymeric |
| Voltage - Max | 33V | 60V |
| Current - Max | 40 A | 10 A |
| Current - Hold(Ih)(Max) | 1.85 A | 750 mA |
| Current - Trip(It) | 3.7 A | 1.5 A |
| Timeto Trip | 2.5 s | 300 ms |
| Resistance - Initial(Ri)(Min) | 50 mOhms | 300 mOhms |
| Resistance - Post Trip(R1)(Max) | 150 mOhms | 950 mOhms |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Size / Dimension | 0.289 L x 0.202 W (7.35mm x 5.12mm) | 0.289 L x 0.202 W (7.35mm x 5.12mm) |
| Thickness(Max) | 0.049 (1.25mm) | 0.049 (1.25mm) |
Frequently asked questions
What are the key differences between the 2920L075/60MR and the 2920L185DR PTC resettable fuses?
The 2920L075/60MR is a 60 V rated device with a hold current of 0.75 A and a trip current of 1.5 A, while the 2920L185DR is a 33 V rated device with a hold current of 1.85 A and a trip current of 3.7 A. Both are surface-mount 2920 (inch) footprint polymer PTC resettable fuses, but they differ in voltage rating, current rating, and maximum interrupt current.
Can the 2920L075/60MR and 2920L185DR be used interchangeably in the same circuit?
No. The 2920L075/60MR is rated for 60 V with a 0.75 A hold current, whereas the 2920L185DR is rated for 33 V with a 1.85 A hold current. Substitution would require verifying that the circuit voltage does not exceed the lower voltage rating and that the load current falls within the hold current window of the replacement device, along with checking trip time, interrupt rating, and thermal derating.
What is the maximum interrupt current for each device?
The 2920L075/60MR has a maximum interrupt current of 10 A at 60 V, while the 2920L185DR has a maximum interrupt current of 40 A at 33 V. These ratings define the highest fault current the device can safely interrupt without damage.
What are the initial resistance values for the 2920L075/60MR and 2920L185DR?
The 2920L075/60MR has a minimum initial resistance of 0.20 Ω and a maximum initial resistance of 0.60 Ω. The 2920L185DR has a minimum initial resistance of 0.030 Ω and a maximum initial resistance of 0.090 Ω. The lower resistance of the 2920L185DR reflects its higher current rating.
What are the trip times for the 2920L075/60MR and 2920L185DR at their respective rated currents?
The 2920L075/60MR trips in a maximum of 1.5 seconds at 3.75 A (5 times its hold current) and a maximum of 5.0 seconds at 1.5 A (2 times its hold current). The 2920L185DR trips in a maximum of 2.5 seconds at 9.25 A (5 times its hold current) and a maximum of 5.0 seconds at 3.7 A (2 times its hold current). Trip time is dependent on ambient temperature and fault current magnitude.
Do the 2920L075/60MR and 2920L185DR share the same package and footprint?
Yes. Both devices are supplied in the 2920 (inch) surface-mount package, which corresponds to a footprint of approximately 7.98 mm × 5.44 mm. They are not drop-in replacements for each other in terms of electrical ratings, but they share the same PCB land pattern and physical dimensions.
What are the operating temperature ranges for these two PTC resettable fuses?
Both the 2920L075/60MR and the 2920L185DR are specified for an operating temperature range of -40 °C to +85 °C. Hold current and trip current must be derated according to the ambient temperature within this range, as published in the manufacturer's derating curves.
Which device is better suited for higher voltage applications?
The 2920L075/60MR is better suited for higher voltage applications because it is rated for 60 V, whereas the 2920L185DR is rated for 33 V. The 2920L075/60MR also has a lower hold current, making it appropriate for lower-current, higher-voltage rails, while the 2920L185DR is intended for lower-voltage, higher-current rails.