To prevent ESD, we must first know what ESD and ESD processes into electronic devices. A charge close to the other conductor of the conductor , it is possible ESD occurs . First , it creates a strong electric field between the two conductors , resulting in the breakdown caused by the electric field . Two voltage exceeds the breakdown voltage between the conductor and the dielectric of air between them , an arc is generated . In 0.7ns to 10ns time, the arc current will reach tens of amps, sometimes even more than 100 amps . The arc has remained in contact until the two conductors short or too low to maintain the current arc so far.
ESD is generated depends on the object 's starting voltage , resistance, inductance and parasitic capacitance : Examples of possible arcing are human , live devices and machines. Examples of possible spikes arc with a hand or a metal object . Or may have the same polarity, the polarity change of the plurality of instances of the arc furniture .
ESD can enter the electronic device is coupled through five ways: the initial electric field can be capacitively coupled to the surface area of the larger networks , and generate up to 4000V / m of high-pressure arc from ESD at 100mm .
Arc injected charges / current can produce damage and failure of the following :. A part penetrating the inner thin insulating layer , the gate of MOSFET and CMOS damaged components ( common ) . b. CMOS devices trigger lock ( common ) . c. shorted reverse biased PN junction ( common ) . d. shorted forward-biased PN junction ( rare ) . e. melting active device inside the welding wire or aluminum wire .
Current causes a voltage pulse on the conductor , the conductors may be power, ground or signal lines , and these voltage pulses to enter each of these components connected to the network ( common ) .
Arc generates a strong magnetic field in the frequency range of 1MHz to 500MHz , and inductive coupling to adjacent routing loops each , far away from the place where ESD arc 100mm generate up to 15A / m current.
Arc radiation of electromagnetic signals are coupled to a long line, play a role in these signal lines receiving antenna ( rare ) .
ESD will find the weak points of the coupling device through various ways . ESD wide frequency range , not just the number of discrete frequencies , it can even enter the narrow-band circuit. To prevent ESD interference and corruption , must be isolated from these paths or strengthen anti- ESD capability of the device.
