PTC resettable fuse for tight board layouts
The Littelfuse 0603L100SLYR is a polymeric PTC resettable fuse from the POLY-FUSE LoRho series, housed in a 0603 (1608 Metric) concave surface-mount package. It holds 1 A continuously and trips at 1.8 A within 300 ms, protecting downstream circuitry from overcurrent faults without needing a fuse replacement.
Hold current and trip performance
Rated for a maximum voltage of 6 V and a maximum interrupt current of 50 A, the 0603L100SLYR fits low-voltage rail protection in portable and battery-powered gear. The 1 A hold current (Ih) at 25 °C ambient means the device stays low-resistance below that threshold; once the fault current exceeds 1.8 A (It), the PTC heats up and switches to a high-resistance state within 300 ms, limiting the current to a safe level. Initial resistance (Ri) is a minimum of 40 mOhms, rising to a maximum of 120 mOhms after tripping (R1). The low initial resistance minimizes voltage drop and power loss during normal operation, which is critical in 6 V rails where every milliohm counts.
Package and board integration
The 0603 (1608 Metric) concave package measures 1.60 mm x 0.80 mm with a maximum seated height of 0.75 mm, making it suitable for dense surface-mount assemblies. Operating temperature range is -40 °C to 85 °C, covering most commercial and industrial indoor environments.
Approvals and compliance
The device carries cURus and TUV approvals, confirming it meets North American and international safety standards for overcurrent protection components.