Design principles for ESD diode protection

Design principles for ESD diode protection

It is said that "no rules, no circles". In the semiconductor industry, engineers must understand the working voltage, current value, application port, and appropriate protection level of electrical equipment when designing protection schemes. Electrical equipment is inevitably threatened by ESD electrostatic discharge. Let's take a look at the basic principles of ESD protection design in the protection plan that engineers need to understand.

ESD diode protection should be designed to balance performance and cost. Pay attention to the following principles:

1) The response speed of the protection circuit should be fast - the rising edge of the IEC61000-4-2 waveform is only 1ns;

2) Capable of handling large transient currents;

3) Consider transient voltage occurring in both positive and negative polarity directions;

4) Control the capacitance load effect and resistance loss effect of signal increase within the allowable range;

5) Consider volume factors to accommodate lightweight portable devices;

6) Product cost factors.

When engineers design ESD diode protection, they usually prioritize using ESD diode discharge diodes, which are overvoltage and anti-static protection components designed for I/O port protection in high-speed data transmission applications. ESD protective devices are used to prevent sensitive circuits in electronic devices from being affected by ESD (electrostatic discharge). It can provide very low capacitance and has excellent transmission line pulse (TLP) testing and IEC6100-4-2 testing capabilities, especially after multiple sampling numbers of up to 1000, thereby improving the protection of sensitive electronic components.

ESD diode electrostatic protection elements can be divided into patch Varistor and ESD diode according to different packages. Engineers can select patch Varistor or diode according to the application port and protection level in the actual selection process. Select capacitance value according to the transmission frequency. The higher the frequency, the lower the device capacitance value. Too large the capacitance value is likely to cause signal packet loss. Therefore, we must select the most suitable ESD according to our own needs.