2021-02-02
ESD electrostatic diode ESD, also known as ESD electrostatic protector, is an overvoltage, anti-static protection element, is a device designed for high-speed data transmission applications I/O port protection. But we commonly used routers, gateways and other equipment, there are a lot of circuit vitality. Therefore, when these devices are manufactured, it is crucial to achieve hardware protection. Next, we follow Liyang Semiconductor to understand a few ESD related knowledge!
First, ESD electrostatic protector diode
First of all, let's understand the ESD electrostatic protector diode. The principle of ESD static protector diode is to connect the ESD static protector diode in parallel with the circuit, when the circuit is working normally, it is in a cut-off state (high resistance state), does not affect the normal operation of the line, when the circuit appears abnormal overvoltage and reaches its breakdown voltage, it quickly changes from a high resistance state to a low resistance state, providing a low impedance conduction path for the instant current. At the same time, the abnormal high voltage is clamped within a safe level to protect the protected IC or line; When the abnormal overvoltage disappears, it returns to the high resistance state and the circuit works normally.
ESD electrostatic diodes, ESD electrostatic protectors, ESD protection diodes, etc., are all protective devices. When protecting circuit elements, the most critical reference factors of these appliances are fast response time, low clamp voltage, and high surge tolerance.
Second, the working principle of ESD diode
Next, let's understand how ESD diodes work. ESD diode has a breakdown voltage. When ESD occurs, the diode reverse voltage exceeds the breakdown voltage, the diode reverse guide passes, and the current is shunt to the ground to protect the circuit; Ideally, when the diode reverse voltage is less than the breakdown voltage, the reverse current should be zero.
Except for the breakdown voltage, of course. Before choosing ESD diode, first understand its operating voltage, that is, the reverse peak voltage. If an ESD diode operating voltage is defined as a current of 10 Na amps. Then we can understand that this operating voltage value is the recommended maximum voltage signal float value. Let's say the diode you choose has a signal range of 0 to 3.6 volts. Then you should choose a diode with Vrwm above 3.6 volts. If you choose a diode operating voltage of less than 3.6 volts, it is prone to current leakage.
Therefore, when the diode is selected, it should be selected according to the working voltage.
