1.5 A hold, 12 V rail — the LoRho advantage for low-voltage protection
The 1206L150/12SLYR is a Littelfuse POLY-FUSE LoRho polymeric PTC rated for 1.5 A hold current at 12 V max. The LoRho designation means initial resistance is just 10 mOhms typical — that is roughly one-tenth the Ri of a standard 1206 PTC at this hold current, so the voltage drop across the fuse at 1.5 A is under 15 mV. Trips in 300 ms at 8 A fault current — fast enough to protect the downstream regulator or connector before the PCB trace temperature rises, but slow enough to ride through inrush from a 10 µF bypass cap bank without nuisance tripping.
Resistance budget and post-trip recovery
Post-trip resistance (R1) maxes at 80 mOhms. After the fault clears and the PTC cools, the resistance settles back near the initial 10 mOhm floor — the LoRho formulation uses a lower-resistivity polymer filler that recovers closer to the original Ri than standard PTCs. For a USB 2.0 port supplying 1.5 A, the I²R loss after a fault event stays under 180 mW, keeping the 1206 package within its thermal budget. The 50 A max fault current rating means this part can survive a direct short to a 12 V lead-acid battery or a 12 V rail with a 600 mOhm source impedance — the PTC transitions to a high-resistance state before the package cracks.
Active lifecycle, approvals, and sourcing posture
The cURus and TUV approvals cover North American and European equipment safety standards; no additional agency review needed for UL 60950-1 or IEC 62368-1 end-product certification. Sourced through authorized and independent distribution channels. The 1206 footprint and tape-and-reel packaging (Cut Tape or full reel) feed directly into a standard pick-and-place line with no MSL bake requirement.