Zener diode micro-assembly protects sensitive electronics

Raychem Circuit Protection, a business unit of Tyco Electronics, recently introduced the PolyZen polymer enhanced, precision Zener diode micro-assembly. Designed to meet the growing need for overcurrent and overvoltage protection on portable equipment that uses barrel jacks for DC power input, the product helps protect sensitive electronics from damage caused by inductive voltage spikes, voltage transients, incorrect power supplies and reverse bias.

PolyZen has a component that protects like a Zener diode but is capable of withstanding very high power fault conditions. The product 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 RoHS-compliant device offers power handling on an order of 100W in a 4mm package and helps provide DC power port protection for portable electronics and systems using barrel jacks for power input, as well as internal overvoltage protection and transient suppression.

PolyZen devices provide protection against multiwatt fault events and require 0.7W power dissipation. In the event of sustained high power conditions, the PPTC element of the device "trips" to limit current and generate voltage drop. This functionality helps protect both the Zener and the follow-on electronics, effectively increasing the diode's power handling capacity, according to Raychem.