Overview

ESD (electrostatic discharge) protection diodes are widely used to protect electronic devices from damage caused by electrostatic discharge. There are many factors that need to be considered to ensure that the diode can effectively protect the circuit without affecting normal operation.

Selection Guide

1.Voltage

  • Working voltage: Select the reverse operating voltage of the diode to be higher than the operating voltage of the circuit to ensure that the diode will not conduct under normal conditions.
  • Clamping voltage: The clamping voltage is the maximum voltage that the diode is limited to during an ESD event. The clamping voltage should be lower than the withstand voltage of other components in the circuit to effectively protect it.

2.Package and Dimensions

  • Choose the right package based on the board space,and common packages include SOD, SOT, etc. For mobile devices or tiny boards, ultra-small packages (such as DFN, QFN, etc.) are more suitable.
  • Make sure the selected package can be installed in the actual circuit and meet the mechanical and thermal requirements.

3.ESD Tolerance Level

  • IEC 61000-4-2: Select devices that comply with this standard. ESD protection diodes usually support different ESD voltage levels, such as 8kV, 15kV, etc. In practical applications, it is recommended to select a voltage level higher than the expected environment.
  • Pulse peak current: The peak current of the diode determines the transient impact current it can withstand. Usually in the ESD protection scenario, it is necessary to ensure that the peak current can cover the target application scenario.

4.Capacitance

The capacitance value of ESD protection diodes affects the transmission performance of high-frequency signals. For high-speed data interfaces (such as USB, HDMI, PCIe, etc.), it is recommended to select diodes with lower capacitance values ​​(such as 0.1 pF - 3 pF) to reduce signal attenuation.
Diodes with low capacitance are more suitable for RF, video and data transmission applications.

5.Response Time

The response time of ESD protection diodes is usually in the picosecond range, and the faster the response, the better. Fast response time helps guide electrostatic transient currents to the ground before they enter the circuit.

6.Bidirectional/Unidirectional Protection

Generally speaking, bidirectional protection is usually selected for AC signals or bipolar interfaces (such as audio interfaces), while unidirectional protection can be selected for DC signal interfaces (such as power lines and signal lines).

About Semiware
Semiware has a comprehensive product lineup of circuit protection device products. The company leverages its technology in the semiconductor field and application background in end products to serve customers in the electronics, automotive and industrial markets. For more information, please visit semiware official website:  https://en.semiware.com/

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