Rf circuit board machining

Small summary to recognize type switch | clamping overpressure device selection points:

Key points of ceramic gas discharge tube selection:

1. Voltage selection

Single use GDT: the arc voltage should be equal to the user's normal working voltage, and leave a certain margin.

Use with MOV: The DC breakdown voltage should be equal to the user's normal working voltage, and leave a certain margin.

2.GDT flow should be determined according to the lightning protection circuit design index, GDT flow should be greater than the lightning protection circuit design flow capacity.

Key points of semiconductor discharge tube selection;

1. The level of signal interface should be **Vs, with a certain margin.

2. Select TSS with different flow rates according to the level of surge to pass through.

3. The normal working current of the circuit cannot match the holding current of the TSS.

Key points of glass discharge tube selection:

1. The DC breakdown voltage should be equal to the user's normal operating voltage.

2. The flow rate of the glass discharge tube should be determined according to the design index of the lightning protection circuit. The flow rate of the glass discharge tube should be greater than the flow capacity of the lightning protection circuit design.

Key points of varistor/patch varistor selection:

1 pressure sensitive voltage to ** the user's normal working voltage, and leave a certain margin;

2. The flow rate of the varistor should be determined according to the design specifications of the lightning protection circuit. The flow rate of the varistor should be greater than the current capacity of the lightning protection circuit.

Key points of selection of transient suppression diode:

The breakdown voltage of S should be equal to the user's normal operating voltage, and leave a certain margin.

2. Use bidirectional or unidirectional TVS according to different application interfaces.

Dc power interface usually uses one-way TVS.

The AC power interface and communication interface generally use TVS in both directions.

3. TVS of different power should be selected according to the level of surge to be passed

Key points of ESD discharge diode selection:

1.ESD breakdown voltage to * the user's normal working voltage, and leave a certain margin.

2. Use bidirectional or unidirectional TVS according to different application interfaces.

The DC power interface is usually one-way.

The AC power interface and communication interface generally use TVS in both directions.

3. The higher the working frequency of the interface, the lower the capacity.

ESD discharge diode product selection ultimately or according to the specific needs of each customer to choose suitable ESD model. When selecting and improving solutions for customers, we must remember to follow the following two principles:

Vdrw≥ the operating voltage on the circuit

According to the application port, the protection level choose the chip varistor or diode, according to the transmission frequency choose the capacitance value, the higher the frequency, the lower the tolerance of the device, too large tolerance is easy to cause signal loss, therefore, must be according to their own needs to choose the appropriate ESD.

Before talking about the development process of domestic EDA, we should first understand the history of EDA industry. In the 1980s, the rapid development of the chip pushed the commercial computer into the high speed, and thus promoted the rise of the CAD industry. EDA is a typical representative.

In the early stage of the IC industry, chip design was achieved by manual wiring. But with the increase of chip integration, the shortage of manual wiring became more and more difficult, which coincided with the rise of the computer, and EDA came into being, which led to the birth of Calma, ComputerVision, Applicon, Mentor Graphics, Daisy and Valid companies. With the help of this electronic automatic tool, they can operate the front and back end technology of the chip design and the verification technology on the computer to help the chip best wiring, verification and simulation.

After years of mergers and acquisitions, only Cadence, Synopsys and Mentor remain in the field of integrated circuit EDA. The influence of markets is also increasingly concentrated. But in fact, since the middle and late 1980s, China has been invested in the research and development of EDA industry.

Data shows that at that time, domestic high-tech fields including integrated circuits were trapped in the "Batumi" embargo, the development was hampered. In order to develop the integrated circuit industry, China mobilized 17 units and more than 200 gathered in the former integrated circuit Design Center in 1986 to develop China's free integrated circuit computer design system -- Panda system.

After many years of difficulties, the first EDA panda system was finally launched in 1993, and the subsequent development can be described as a step by step in 10 years. In 2001, the domestic IC design unit launched the Zeni system of Jiutian, which attacked the overseas market while serving the local demand. In 2009, * set up a new company, Huada Jiutian, to promote the development of domestic EDA. This will be later.

Although due to subjective and objective reasons, the domestic EDA industry did not succeed in the secular sense, but in this process, there have been a number of EDA manufacturers sprout in China. According to the relevant data, in 2008, the domestic EDA research companies also have China Electronics, Huatian Zhonghui, core vision, Exeli, Shengjing micro, technology industry thinking, Guangli micro and the United States and other several. After another ten years of development, Huada Jiutian, Xinhe Technology, Guangliwei, Bodawei and other enterprises broke out from the domestic EDA formation:

Bearing the technology of Panda system, Huada Jiutian has accumulated many years in EDA and IP. Now they can provide digital-analog hybrid/fully customized IC design, FPD whole process design and SoC digital back-end optimization direction of EDA solutions. Especially in the field of FPD, Huada Jiutian * has become the best supplier of FPD design solutions for the whole process, and has gained the market share of most panel factories.