Polymeric PTC Resettable Fuse 6V 3 A Ih Surface Mount 1812 (4532 Metric), Concave
The 1812L300MR is a surface-mount resettable fuse (PPTC – Polymer Positive Temperature Coefficient) designed to provide overcurrent protection in electronic circuits. When excessive current flows, the device increases its resistance sharply, limiting current to a safe level. Once the fault condition is removed and power is cycled or reduced, the device resets automatically.
This component is commonly used in power supply lines, battery-powered devices, USB ports, and general consumer electronics where resettable protection is preferred over one-time fuses.
Key Features
Resettable overcurrent protection device (PPTC technology)
Surface-mount package (1812 footprint)
Automatic recovery after fault removal
Low resistance in normal operation
Fast trip response to overcurrent events
RoHS compliant and lead-free
Electrical Characteristics
Hold Current (I_hold): 3.0 A
Trip Current (I_trip): ~6.0 A
Maximum Voltage Rating: 6 VDC
Maximum Current Rating: 40 A (short duration fault)
Initial Resistance (R_min / R_max): ~0.015 Ω / 0.050 Ω
Trip Time: Dependent on current and ambient conditions
Thermal Characteristics
Operating Temperature Range: -40°C to +85°C
Storage Temperature Range: -40°C to +85°C
Typical Power Dissipation: Dependent on fault condition
Mechanical Characteristics
Package Type: Surface Mount (SMD)
Package Size: 1812 (4.5 mm × 3.2 mm approx.)
Termination: Nickel barrier with matte tin plating
Mounting: Reflow solder compatible
Applications
Power supply protection
USB and peripheral ports
Battery pack protection
Consumer electronics
Industrial control circuits
Compliance and Standards
RoHS compliant
Halogen-free (depending on manufacturer variant)
UL recognized (check specific manufacturer certification)
Notes
Trip and hold currents are specified at 25°C; derating is required at higher temperatures
Device performance depends on PCB layout and thermal environment
Proper spacing and copper area improve heat dissipation and reliability