Temperature Control in Mobile Phones Using SMD NTC Thermistors

摘要

In the past few years multilayer NTC thermistors with Ni-barrier termination have become state of the art for temperature control in a variety of applications in the telecom and automotive industries. Thanks to the availability of SMD NTC in small case sizes down to 0402 integrated temperature sensing in hybrid electronic circuit modules is now available. The scope and purpose of this paper is to describe the specific tasks of NTC thermistors in mobile phone applications for temperature measurement and compensation. Future design trends with respect to the required case sizes and resistance tolerances are discussed. In addition reliability requirements are given in detail. Multilayer technology with inner electrodes as key technology for SMD NTC thermistors ensures high design flexibility and improved long time reliability. Detailed reliability measurements in high humidity and high temperature environment have been performed and are reported.