Automotive polySwitch resettable PPTC devices give design flexibility

April 18, 2017 // By Nick Flaherty
Littelfuse has introduced three series of PolySwitch AEC-Q200 qualified resettable Polymeric Positive Temperature Coefficient (PPTC) surface mount devices to provide overcurrent protection in harsh automotive environments.

Unlike fuses, resettable PPTCs do not require replacement after a fault event; they allow the circuit to return to the normal operating condition after the power has been removed and/or the overcurrent condition is eliminated. 

The largest of the new devices, the 2920-size ASMDC Series, has a lower profile compared to existing 2920 size ASMD series surface mount PPTCs, and no heavy metal terminals. It also offers the highest holding current and voltage rating of the three. The two smallest of these new devices, the 0603-size femtoASMD Series and the 0805-size picoASMD Series, are ideal for applications in crowded automotive electronics boards. 

Typical applications for the ASMDC, femtoASMD, and picoASMD Series Resettable PPTCs include automotive infotainment, communications (GPS navigation), network (CAN Bus, LIN bus), body electronics (door locks, lumbar pumps), security (keyless entry, rearview camera), ADAS (advanced driver assistance system) and climate control systems.

“The choice of compact footprint or low profile packaging combined with AEC-Q200 qualification make these SMD resettable PPTCs ideal for overcurrent and short-circuit protection under the hood,” said Yong Zhang, product manager, PPTC Devices at Littelfuse. “Together, they extend the wide range of form factors, operating currents, and voltage ranges Littelfuse offers, and give automotive electronics designers greater design flexibility.”

The smaller picoASMD Series and femtoASMD Series devices provide a wider range of form factors to enhance design flexibility, while the low profile ASMDC Series helps circuit designers meet the ever-increasing demand for compact and space-saving designs as the amount of electronics content in vehicles grows.

The resettable solutions are designed to guard against overcurrents and short circuits in automotive circuitry restore systems to operation after the fault condition is resolved.

The surface mount PolySwitch ASMDC, femtoASMD, and picoASMD Series Resettable PPTCs are available in tape and reel packaging in quantities of 4,000 or 3,000.

www.Littelfuse.com