Precision Zener Diodes protect Automotive Infotainment Peripherals

The PolyZen micro-assembly incorporates a stable Zener diode for precise voltage clamping and a resistively non-linear, polymer positive temperature coefficient (PPTC) layer that responds to either diode heating or overcurrent events by transitioning from a low to high resistance state. The device helps provide coordinated protection with a component that protects like a Zener diode, but is capable of withstanding very high power fault conditions without requiring any special heat sinking structures beyond normal printed circuit board traces.

By clamping and smoothing inductive voltage spikes, PolyZen devices help shield downstream electronics from overvoltage and reverse bias. Additionally, their high power absorption capability protects against faults that occur when using an incorrect or misconnected power supply.

Because PMPs offer larger display panels and video processing capabilities, they require more power and draw higher current than prior-generation portable devices. Multiple interfaces and charging systems can also expose these devices to damage caused by misconnection of the 5V and 12V lines. The new PolyZen devices are capable of withstanding the high inrush currents and faults associated with the new technology, and are available in a small form factor that is suitable for PMPs.

Portable digital entertainment is quickly making the leap from audio-centric devices such as MP3 players to multimedia products that play video and digital images. This shift is putting portable media players at the center of the digital lifestyle, said Tuan Tran, global product manager for Tyco Electronics. The new PolyZen devices with higher hold currents help consumer electronics manufacturers meet safety requirements, enhance customer satisfaction and reduce warranty costs in the rapidly expanding PMP market.