The following graph shows the resistance deviation and electrical characteristics of the products developed (two models in the NTCG Series) based on the resistance specifications of industry-standard, high accuracy thermistors used for temperature control in battery packs.

Resistance deviation and electrical characteristics of the product developed

To tackle another issue of adding sufficient resistance against electrostatic discharge, improvement of the internal chip struture — in other words, upgraded high-accuracy process controlling technology — will be essential.

Strengthening anti-static properties

As explained in the previous section, there are two types of chip NTC thermistors:the single plate type and the multilayer type. The single plate type is superior in terms of resistance to static electricity.

Nothing except the thermistor element is between the terminal electrodes, and surge current flows through the whole of it, meaning that it is not severely affected by static electricity. However, in the multilayer type, surge current from a terminal electrode passes through the thermistor layer situated between the internal electrodes, which are much closer together that those in the single plate type, and moves on to the other terminal electrode. In doing so, the voltage voltage is directly applied between the internal electrodes.

To provide sufficient anti-static properties, we need to establish a mass production technique that generates uniform and fine thermistor crystals, and need to control the microstructure of the internal electrodes with a precision on the order of microns. In particular, commercial production of the ultra-miniature 1005 type, requires highly advanced controls in the electrode formation process.

As a matter of course, the recently-developed high-precision products have overcome all of these technical problems with excellent anti-static discharge properties. The results of an anti-static test is shown below. The 1005 type, in addition to the 1608 type, demonstrates superb stability in resistance and B constant.

Results of anti-static tests

Future efforts

As the volume of transmission data handled by portable devices that use battery packs increases, demand for multi-functionality, as well as for smaller and lighter units, will continue to increase. In an age in which products are increasingly digitized and images are recorded using digital signals, development of optical, broadcasting and mobile telecommunications networks for high-speed transmission of enormous amounts of information to individuals and homes has been accelerating.

At the same time, however, we will also face a variety of “temperature problems”, such as difficulties with heat discharge design, as circuits become smaller and thinner and as products incorporate remarkable technological innovations. Other problems may be experienced with the IC chips themselves, which are directly affected by temperatures as peripheral components are integrated into IC packages. On the whole, it is conceivable that electronic appliances and circuits will have to operate in increasingly intense temperature environments.

It is in this type of environment that we strive to make further technological innovations through-out all processes, from the development of new material compositions for thermistors to research and development and production technologies that lead to the development of mass production systems, with the purpose of attaining further miniaturization, narrower tolerances and lower costs. In these ways, we are responding to the growing need for high accuracy temperature control.