MF-R900

PTC Resettable Fuses is a type of polymeric positive temperature coefficient (PPTC) thermally-activated device used for the protection of electrical products. The MF-R900 is the latest in PTC Resettable Fuse technology from Murata/OKI and is designed to meet the demands of the industrial, automotive and consumer markets. It offers superior overcurrent protection, fast tripping time, and accurate and stable trip level characteristics.

The MF-R900 re-startable fuse is a single-usage resettable device offering low resistance and high protection characteristics. It features a high melt point with an operating temperature range of -40°C to +125°C. The device consists of a polymeric material encapsulated inside two metal electrodes. When the device is exposed to an overcurrent, the temperature in the device rises, causing the internal polymeric material to expand and creating a high resistance state. The device will remain in a high resistance state until the overload is removed and the device cools to its normal operating temperature, at which point it will reset and return to its original low-resistance state, ready for reuse. As such, the MF-R900 is ideal for applications that require low-impedance and high protection.

The MF-R900 is suitable for many portable devices such as smartphones, tablets, medical and IoT tools. It meets the demands of these applications by offering excellent overcurrent protection, fast tripping time, and accurate and stable trip level characteristics. Additionally, the device is highly reliable, with a minimum load life of at least 36,000 cycles, and it offers high temperature cycling of ±135°C. Finally, the MF-R900 offers very low insertion loss of less than 0.3 mΩ, enabling the application to benefit from the lowest possible voltage drop.

The working principle of the MF-R900 is as follows. When the device is exposed to an overcurrent, the temperature in the device rises. As this temperature exceeds the device\'s trip level, the internal polymeric material expands, creating a high resistance. This creates a rapid increase in the voltage across the device which reduces its current carrying capability. This in turn causes the current flowing through the device to drop quickly, reaching a steady-state level. Once the overload is removed, the device cools and returns to its original low-resistance state, ready for reuse.

In summary, the MF-R900 is designed to meet the demands of a wide variety of portable device applications. It offers superior overcurrent protection, fast tripping time, and accurate and stable trip level characteristics. Additionally, the device is highly reliable, with a minimum load life of at least 36,000 cycles, and it offers an extremely low insertion loss of less than 0.3 mΩ. As such, the MF-R900 is ideal for applications where low-impedance and high protection are required.