Router specific crystal selection and analysis of common problems in crystal application
Router specific crystal selection and analysis of common problems in crystal application
First of all, high performance quartz smd crystal oscillator is the premise of the smooth use of the router.
Our life has become more and more dependent on the convenience brought by the network,
and the router is the necessary network equipment for us to connect with "WiFi".
Routers can help you connect multiple computers at the same time, and realize the sharing of Internet and LAN.
When the router network cable interface receives the Internet data,
the quartz chip inside the smd crystal oscillator provides accurate and stable clock signal reference for the chip through mechanical deformation (piezoelectric effect),
and the chip completes decoding, sending and completing the instruction program.
If the smd crystal oscillator of the router is unstable, such as serious frequency offset or stop frequency output, what will happen to the router?
Frequency offset will directly lead to unstable data upload and download in router network, such as network speed slowing down or disconnection.
The system could not start and was disconnected directly.
Router requirements for smd crystal oscillator:
In view of the fact that the router works continuously for a long time, sometimes as long as several months,
there are clear regulations on the continuous and stable output mode frequency of smd crystal oscillator.
The error of frequency should be less than 20ppm. Once the error is exceeded, it will lead to network data upload and download errors.
In addition, due to the influence of temperature coefficient, the router PCB itself has heat generation, and the temperature is about 30 ℃ ~ 45 ℃.
smd crystal oscillator works continuously in high temperature environment, and the phenomenon of "temperature drift" is easy to occur.
"Temperature drift" refers to the influence of high and low temperature on the output frequency of smd crystal oscillator. At the same time,
with the passage of time, the crystal will slow down aging, crystal frequency offset will become increasingly serious.
Once the actual output frequency of the smd crystal oscillator exceeds the accuracy requirements of the chip, the router may not work normally.
Introduction of router smd crystal oscillator
In terms of dimensions, SMD2520 and SMD3225 are commonly used in routers. There are 12Mhz, 25MHz, 26MHz, 40MHz in frequency.
High precision and high stability smd crystal oscillator can help routers better receive network signals and process them quickly.
Low precision smd crystal oscillator will weaken the function of receiving signals and reduce network speed, Therefore,
when choosing smd crystal oscillator, we must choose regular smd crystal oscillator manufacturers. In the manufacturing process,
we will tighten the quality control of smd crystal oscillator in "temperature drift" and frequency stability,
which is also a strong guarantee for router equipment to achieve stability and high-speed network data transmission.
Solution of router smd crystal oscillator fault
If the router adopts the active smd crystal oscillator scheme, connect the power supply according to the requirements (pay attention to the size of
the input voltage and the smd crystal oscillator voltage input pin), and test whether the smd crystal oscillator output terminal has frequency output.
If it is a passive smd crystal oscillator scheme, the resistance between its two pins should be infinity by measuring the 10K gear of the universal meter,
which means that it does not leak electricity at first. Crystal leakage shows that the crystal itself is bad.
The smd crystal oscillator is welded on the working circuit of the circuit board which has been verified to be OK,
and its working frequency is measured with a frequency meter or oscilloscope to determine whether the smd crystal oscillator stops or the frequency deviation exceeds the tolerance.