ESD electrostatic diode selection

The fast recovery diode circuit is supplied with the specified IF by a DC current source, and the pulse generator passes through the isolation capacitor C and adds a pulse signal. The trr value observed by an electronic oscilloscope is the time it takes from the time I=0 to the time IR=Irr.

Assuming the reverse recovery charge inside the device is Qrr, there is a correlation equation

Trr ≈ 2Qrr/IRM

When the IRM is constant, the smaller the reverse recovery charge, the shorter the reverse recovery time.

ESD electrostatic diode selection:

1. When using ESD static diodes, they are connected in parallel to the protected circuit and should not have any impact on the operation of the circuit under normal circumstances;

2. Selection of breakdown voltage VBR: The breakdown voltage of the ESD tube should be greater than the maximum working voltage Um of the line or the maximum voltage value of the signal level;

3. Selection of pulse peak current IPP and maximum clamping voltage VC: When using ESD DIODES, the appropriate model of IPP should be selected based on the maximum surge current that may occur on the line. It should be noted that the maximum clamping voltage VC at this time should not be greater than the maximum peak voltage that the protected chip can withstand;

4. When used for signal transmission circuit protection, it is necessary to pay attention to the frequency or transmission rate of the transmitted signal. When the signal frequency or transmission rate is high, low capacitance series pipes should be selected, otherwise it will affect the communication quality.

Packaging form of electrostatic diodes: Select the appropriate packaging form based on the circuit design layout and the number of protected circuits. (Note that the packaging size can to some extent reflect the protective power of the device. Generally, the larger the packaging, the higher the protection level of the device, and vice versa.)

An electrostatic protector is an overvoltage and anti-static protective component used to protect sensitive circuits in electronic devices from the influence of ESD (electrostatic discharge). Its function is to transfer ESD stress from sensitive components, allowing current to flow through the protective component rather than the sensitive component, while maintaining low voltage on the sensitive component; ESD electrostatic protectors should also have low leakage and low capacitance characteristics, without reducing circuit functionality; Will not cause damage to high-speed signals, and the function of protective components will not decrease under multiple stresses