What is an ESD protection diode?

 An ESD (electrostatic discharge) protection diode is a type of Zener diode optimized for ESD protection applications. They are a simple and low cost way to protect electronic circuits from release of stored static electricity on common touchpoints like USB ports and buttons. There are diodes for a wide range of signal voltages with protection up to 30 Kilovolts! A slightly different device is a TVS or transient voltage suppressor diode which can protect from lightning surges, switching surges and signal ripples. ESD protection diodes remain silent in the absence of electrostatic discharge. They protect integrated circuits in the event of an excessive electrostatic discharge.


An ESD diode is a type of PN semiconductor junction designed to be used in reverse bias. Beyond the avalanche breakdown voltage, avalanche breakdown as discussed in the case of TVS diodes occur and that voltage can be called Zener voltage. Zener voltage can be optimized by the dopant densities in the N and P type regions that form the PN junction. ESD diodes are also connected parallel to the input of the circuit which it protects and conducts to shunt the ESD to ground in case of occurrence of ESD. Need for ESD protection in a circuit can be assessed by ESD simulation using transmission-line pulse (TLP) waveform. TLP technique is based on charging a long cable to a predetermined voltage and discharging it into a device under test (DUT).


Testing ESD protection

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