The inrush current occurs in power supply circuits (LED driver board, inverter fluorescent lamps, heaters, etc.) when electric equipment switches on. It will be about a hundred times higher than normal operating current. The surge current may destroy the device. Therefore it is supposed to be suppressed. Chip power NTC is one of the most effective and simple measures to solve the inrush current problem in AC-DC power supply circuit.
NTC resistance at room temperature is big enough to suppress inrush current when the equipment switches on. After that, as the body temperature of NTC rises, its resistance becomes smaller, and thus the power consumption of NTC is negligible to ensure that electric equipment working normally.
Sunlord now presents the SPNT series chip power NTC thermistor. Compared with traditional Pin-type power NTC thermistor, SPNT series provides better performances:
1） The diameter of Pin-type power NTC ranges from 6.5mm to 30mm, while chip NTC can provide at least 50% smaller area to take up less PCB real estate.
2） The height of chip NTC is only 1/4 of that of Pin-type NTC, which will save more space and make machines slimmer.
3） SMD components can be laid on both sides of PCB to achieve flexible layout.As to electrical characteristics performance, SPNT series provides:
1） The material resistivity of Pin-type is very low (50-200m•mΩ) which results in low B constant and high Residual Resistance.
2） Chip power NTC adopts innovative materials with high resistivity (5000m • mΩ or so) and internal electrode structure, and thus provides high B constant (4000K or more) and low Residual Resistance.

R-T Characteristic Curves (representative) of SPNT series chip power NTC thermistor are shown as following figure:
 

From above figure we can see that with developed material, SPNT series presents high B constant (4000K or more) and low Residual Resistance.
With the development of IC technology, electronics products tend to be slimmer which requests more chip components. Thanks to its small size and low residual resistance, Chip power NTC well meets the request and is especially applicable for the following fields:
1） LED lighting driver, energy-efficient lighting driver
2） LCD-TV
3） Adapter of Notebook, cell phone, etc.
4） UPS
5） Power supply of other household appliances