Epson Crystal Vibrator Agent tells you how important it is to choose the initial type of Crystal Vibrator.
Release date:2018-12-17 Author:Guan Shuo Click:
The key work of electronic product development is principle design, component selection, validation test and so on. Selection of components is a very important part of it. Experienced hardware design engineers attach great importance to component selection. However, after all, the technology industry has expertise, hardware engineers can not concentrate all their energy on the selection of components. Component selection requires a lot of knowledge and information. Although the principle of components itself seems very simple, all students majoring in electronic technology need to learn some knowledge of the principle of components. But these principles are highly idealized models, and the components in reality are far more complex than these models. And there are tens of millions of components. It is not easy to master them one by one. So, just for the mastery of component technology, we need professionals to study. If you choose the right one, the less trouble you will encounter in the process of product design, the lower the cost, and the faster the project progress. Therefore, in the early stage of selection, more running-in and communication with component manufacturers are needed, and a professional manufacturer becomes more and more important.
Crystal components have been widely used in various electronic devices, such as mobile phones, personal computers, printers, projectors, smart homes, smart watches, automotive electronics and so on. It can be said that almost all electronic products will use it, and it is also a very critical device. Crystal oscillators are like clocks and watches in electronic devices, giving CPUs time perception. So today we're going to talk about crystal oscillator, how do component engineers choose it?
Initial selection steps
1. Choose crystal types according to their own applications
At present, many engineers are not particularly familiar with crystals. Crystals are classified into active crystals (crystal oscillators) and passive crystals (crystal oscillators).
The first step is to determine whether you are using source or passive.
What's the difference between passivity and activeness? Actually, it's very simple. Active power is a separate power supply port. Passive means that there is no separate power supply port. In a more popular way, passive crystals need external components to help them start up. Active crystals only need to turn on the voltage to start up.
For example, many designs follow previous design drawings. Look at the schematic diagram and confirm the type of crystal used in the previous design. There are two load capacitors on the periphery of the passive crystal, which is an obvious sign. The active crystal has a VCC power supply terminal. It's easy to distinguish. Active crystals must be used for power supply
A According to the crystal requirements
For example, the product renewal rate is low, the phase noise is good, the frequency deviation in the whole temperature range is low, and the temperature requirement is high. Active crystals are needed. For example, Epson's ordinary active crystal SG series, SG-210STF, SG7050, temperature compensation crystal TG2520, TG-5006, or real-time clock module RTC.
B According to application category
Network products, long life, high application environment requirements, high communication quality, often use active crystals with functions, such as TCXO, V-TCXO, low jitter SPSO.
Consumer products, fast updating, low requirements, generally more passive crystals.
Industrial products, update slowly, generally, most of them use ordinary active crystals, long-term stability is better.
2. DETERMINATION OF CRYSTAL PARAMETERS
After determining the type of crystal selection, we further determine the parameters to be selected according to whether the crystal is passive or active.
Passive crystals confirm the following parameters: frequency accuracy, load capacitance, operating temperature, size, frequency offset requirements in full temperature range.