What is Network Transformer

What is Network Transformer

Network transformers include T1/E1 isolation transformer, ISDN/ADSL interface transformer, VDSL high-pass/low-pass filter module, interface transformer, T3/E3, SDH, 64KBPS interface transformer, 10/100BASE, 1000BASE-TX network filter, DC-DC converter and special transformer according to customer needs. Products are mainly used in: high-performance digital switches; SDH/ATM transmission equipment; ISDN, ADSL, VDSL integrated services digital equipment; FILT optical loop equipment; Ethernet switches and so on, such as Yutai Electronics YL18-2050S, T37-1107S and so on more common!

 

The Function of Network Transformer

Network transformer mainly has the functions of signal transmission, impedance matching, waveform repair, signal clutter suppression and high voltage isolation.The Role of Network Transformer in EthernetIn Ethernet equipment, when RJ45 is connected through PHY, a network transformer will be added in the middle. Some transformers have central taps connected with power supply, and others with capacitors to the ground. And when connected to the power supply, the power supply value can be different, 3.3V, 2.5V, 1.8V have.

 

The function of this transformer is analyzed as follows:

1. Why do middle taps have some power connections? Some grounding? This is mainly determined by the type of driver used in the UTP port of the PHY chip. There are two types of driver, voltage driver and current driver. Voltage-driven is connected to the power supply; current-driven is directly connected to the capacitor to the ground. So for different chips, the connection of the central tap is closely related to PHY. Specifically, we should refer to the data sheet of the chip and the reference design. 
2. Why are different voltages connected to the power supply? This is also determined by the UTP port level specified in the PHY chip data used. At what level you decide, you have to connect the corresponding voltage. That is, if it is 2.5v, it will pull up to 2.5v, and if it is 3.3v, it will pull up to 3.3V. 
3. What is the function of this transformer? Can it be disconnected? In theory, it can be connected directly to RJ45 without transformer, and it can work normally. However, the transmission distance is very limited, and when connected to different levels of network ports, it will also have an impact. And the external interference to the chip is also great. When the network transformer is connected, it is mainly used for signal level coupling. Firstly, it can enhance the signal and make the transmission distance farther; secondly, it can isolate the chip from the outside, enhance the anti-interference ability, and increase the protection of the chip (such as lightning strike); thirdly, when receiving different levels (such as PHY chip is 2.5V, some PHY chip is 3.3V), it will not be right. Influences on each other's equipment.