On June 6, 2019, the Ministry of Industry and Information Technology issued four 5G licenses, marking China's official entry into the 5G first year and becoming the first echelon of 5G commercial. China has become the fifth commercial 5G country after South Korea, the United States, Switzerland and the United Kingdom. It’s not easy to go on for 20 years! What makes 5G is a new era of ubiquitous data connectivity, and the possibilities it brings are endless.
With professional statistics, there are more than 5 million 4G base stations in the world, there are more than 3.3 million in China, and the scale of 4G users is as high as 1.1 billion! Now 5G is licensing, and a behemoth is starting. It is predicted that within three years, three domestic operators will build more than 3 million 5G base stations, and the number of 5G users in China will exceed 460 million in 2025.
*The above content is from the "e planet" public number
Regardless of the current external environment, the arrival of the 5G era seems overwhelming.
So in this era, what products of TDK's varistor can help?
The above figure lists varistor that can be used in the field of information communication. product. Today we focus on introducing the thermal protection varistor.
Thermal protection varistor can be used for base station surge protection devices. It uses a design that integrates a varistor and a thermal fuse function into one component.
● The varistor function is used to protect electronic devices from voltage surges
●  The thermal fuse function is used to disconnect the load varistor from the circuit
Typical circuit diagram
Currently available thermal protection varistors Designed
Single Wire Design
How it works:
; ● Single wire bond as thermal fuse
● Thermal fuse is broken after melting
; ● Small size, easy to install
● Poor reliability
● Single wire bond There is a risk of reconnection after melting
● Disconnection cannot be guaranteed
and our thermal protection varistor Embedded design is used
How it works:
● Spring and wire are also used as thermal fuses
● Once the wire is melted, the spring will automatically disconnect.
● High reliability
● Spring design will increase the distance of disconnection
● Ensure complete break Open
Application of Thermally Protected Varistors in RRU
RR U (Remote Radio Unit) is a remote radio unit that is used to be called a remote control unit to separate the baseband unit from the transmitting unit. The difference from the repeater is that the repeater amplifies and transmits the base station RF signal reception, but the noise is amplified at the same time, while the RRU (Radio Frequency Remote Control Unit) does not.
MT series thermal protection varistor is especially suitable for RRU power protection
MT25 Thermally Protected Varistors Can Be Used in Modules for Multiple Surge Protection Devices
● The UL1449 and UL60691 certified thermal protection MOV series can be used directly in the modules of various surge protection devices
● Embedded Design
● Surge Rating Imax=20kA/15kA, In=10kA
● In Overvoltage Test The limiting current is 10A
● Thermal protection can be connected in parallel with the load and protected.
● Compact and sturdy design can Install to Surge Protection Module
● Indication can provide a safe and simple circuit monitoring function