0402L050SLKR - 0.5A PPTC Resettable Fuse 6V 0402 | Littelfuse
MPN: 0402L050SLKR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.34 | $0.34 |
| 10 | $0.21 | $2.10 |
| 100 | $0.14 | $14.00 |
| 500 | $0.12 | $60.00 |
| 1,000 | $0.1058 | $105.80 |
Drop-in alternatives for 0402L050SLKR β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
0402L050SLR
β Drop-Inπ Reference alternative (not in catalog)
0402L075SLR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
0402L100SLR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
0402L150SLR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
0402L200SLR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
0402L050SLKR Maximum Ratings & Electrical Characteristics
| Device Type | Polymeric PTC Resettable Fuse (PPTC) |
| Series | 0402L LoRho POLY-FUSE |
| Hold Current (Ih) | 500 mA |
| Trip Current (It) | 1 A |
| Maximum Voltage | 6 VDC |
| Maximum Fault Current (Imax) | 50 A |
| Initial Resistance | 0.04 ohm |
| Power Dissipation | 0.5 W (1/2 W) |
| Time to Trip | 0.1 s |
| Package | 0402 (1005 Metric), Concave |
| Mounting Type | Surface Mount |
| Solder Compatibility | High-temperature solder compatible |
| Response Characteristic | Fast response to fault currents |
| Reset Behavior | Automatically resettable after fault removal |
| Termination Style | SMD Solder Pad |
| Packaging | Tape & Reel (T/R) |
| RoHS Status | Compliant |
0402L050SLKR Pin Configuration
| Pin 1 | Terminal 1 β PPTC series terminal - connect to supply or load (non-polarized, either orientation) |
| Pin 2 | Terminal 2 β PPTC series terminal - connect to load or supply (non-polarized, either orientation) |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
0402L050SLKR is suitable for 6 applications: USB Port Overcurrent Protection, Smartphone and Tablet Battery Protection, IoT and Wearable Device Rail Protection, Hard Disk Drive and Peripheral Protection, Consumer Electronics Board-Level Protection, Automotive Infotainment Accessory Rails.
USB Port Overcurrent Protection
The 0402L050SLKR is ideal for USB VBUS overcurrent protection in smartphones, tablets, and accessories: its 6 VDC rating covers the 5 V USB rail with margin, its 500 mA hold current matches USB 2.0 unit-load budgets, and the 0.04 ohm LoRho resistance drops only about 20 mV at full load, preserving voltage accuracy at the connector. Placed in series with VBUS near the port, the PPTC trips in approximately 0.1 s on a short-circuit fault, then automatically resets after the fault is removed - no field service required. For USB 3.0 or BC1.2 high-current ports, select a higher-hold-current 0402L family member on the same footprint.
Recommended
Smartphone and Tablet Battery Protection
Battery-powered consumer devices need compact, resettable overcurrent protection on charge and discharge paths. The 0402L050SLKR fits because 0402 (1005 metric) is one of the smallest PPTC footprints available, the 6 V rating suits single-cell Li-ion boost rails, and the low 0.04 ohm resistance minimizes runtime loss - important because every milliohm in the discharge path wastes battery energy as heat. Installed between the battery protection IC output and the load rail, the device limits fault current during short events and recovers after the condition clears. Note hold-current derating at elevated ambient temperatures near hot battery compartments.
Recommended
IoT and Wearable Device Rail Protection
IoT sensors, smart tags, and wearables concentrate dense circuitry into tiny enclosures where a single fault must not require product replacement. The 0402L050SLKR provides resettable protection for 3.3 V and 5 V logic and radio rails: its 500 mA hold current covers typical BLE/Wi-Fi module average loads, and its 0.1 s time-to-trip limits fault energy that could damage the radio SoC or PMIC. The 0.5 W dissipation rating is generous for the size, but designers should keep the device away from hot RF power amplifiers since ambient heat reduces the effective hold current via derating.
Recommended
Hard Disk Drive and Peripheral Protection
HDDs and hot-pluggable computer peripherals use surface-mount PPTCs on their 5 V and 12 V supply lines so that a downstream short does not destroy the drive or the host port. The 0402L050SLKR suits 5 V low-power drive rails with its 500 mA hold and 6 V rating, while the LoRho 0.04 ohm resistance keeps the supply impedance low for spin-up transients. Because the device resets automatically, drive returns from an overcurrent event without RMA. For 12 V rails or higher-current SATA power lines, step up within the 0402L family or to larger PolySwitch packages on the same protection strategy.
Recommended
Consumer Electronics Board-Level Protection
Set-top boxes, audio accessories, cameras, and small appliances embed 0402 PPTCs on accessory ports, motor drivers, and auxiliary rails. The 0402L050SLKR is attractive at BOM level: at approximately $0.10 per unit in volume (as of 2026-09-14), resettable protection costs a fraction of a one-time fuse plus warranty service. Its concave 0402 termination supports standard lead-free reflow, and high-temperature solder compatibility ensures reliability through multiple reflow passes during board assembly. Designers should place the device upstream of the connector and follow the datasheet pad layout for accurate trip behavior.
Recommended
Automotive Infotainment Accessory Rails
Non-critical accessory rails inside vehicle infotainment and telematics units (USB charging ports, microphone bias, backup-camera 5 V supplies) benefit from resettable PPTC protection because field fuse replacement is costly. The 0402L050SLKR protects post-clamped 5 V rails after a load-switch or TVS front end; its 6 V rating fits regulated 5 V, and the 0.04 ohm resistance limits voltage drop for charging compliance. Designers must confirm AEC-Q requirements separately - standard 0402L parts are consumer grade, and Littelfuse offers dedicated automotive PolySwitch series where qualification is mandatory.
Recommended
Recommended Products Summary
Engineering reference data for 0402L050SLKR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | 0402L050SLR | 0402L075SLR | 0402L100SLR | 0402L150SLR |
|---|---|---|---|---|---|
| Package | 0402 (1005 Metric), Concave | 0402 (1005 Metric) - same | 0402 (1005 Metric) - same | 0402 (1005 Metric) - same | 0402 (1005 Metric) - same |
| Brand | Littelfuse | Littelfuse | Littelfuse | Littelfuse | Littelfuse |
| Hold Current | 500 mA | 500 mA | 750 mA | 1.0 A | 1.5 A |
| Trip Current | 1 A | 1 A | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
| Maximum Voltage | 6 VDC | 6 VDC | 6 VDC | 6 VDC | 6 VDC |
| Initial Resistance | 0.04 ohm | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
| Maximum Fault Current | 50 A | 50 A | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
| Time to Trip | 0.1 s | 0.1 s | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
| Power Dissipation | 0.5 W | 0.5 W | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
Key Differentiators
- Ultra-low 0.04 ohm initial resistance (LoRho grade) (vs 0402L050SLR)
- Smallest PPTC footprint for 500 mA hold current (vs 1812L050)
- Low 0.5 W dissipation rating for the size class (vs 0402L100SLR)
Design Notes
The 0402L050SLKR dissipates up to 0.5 W at rated hold current - significant for a 0402 chip. Estimated: at 500 mA through 0.04 ohm initial resistance, steady-state dissipation is only I2R = 10 mW, but near the trip region internal resistance rises sharply and heating accelerates. PPTC trip behavior is thermally coupled to the PCB: hold current derates to roughly 80 percent at elevated ambients. Keep the device away from power MOSFETs, RF amplifiers, and other heat sources, and verify the trip point at maximum expected ambient in system-level testing.
Follow the Littelfuse recommended 0402 (1005 metric) land pattern exactly - pad size affects the thermal path and therefore the trip current. The device is non-polarized, so orientation does not matter during assembly, which simplifies pick-and-place. Use a solid copper trace capable of carrying the full fault-limited current (up to 50 A is the device rating, but downstream wiring limits apply). Place the PPTC in series near the connector or battery terminal so the entire downstream circuit is protected, and avoid paralleling traces that bypass the device.
Three common mistakes: (1) sizing hold current equal to the load current - instead choose Ih roughly 1.3 to 1.5x the maximum continuous current to prevent nuisance trips from ambient heat and tolerance; (2) exceeding the 6 VDC or 50 A ratings - the device can crack or fail to trip safely on fault currents above Imax; (3) forgetting post-trip recovery - after tripping, resistance stays elevated until the polymer cools, and the circuit will not return to full current capability immediately; allow cool-down and a power cycle in reset-sensitive designs.
Compliance Information
RoHS compliance per DigiKey/Littelfuse product listings; high-temperature solder compatibility per Littelfuse datasheet indicates lead-free process compatibility. REACH, halogen-free, and conflict-minerals declarations not published in retrieved data - request official compliance certificate from Littelfuse.
