It indicates that the chassis is coated with insulating paint, PCB board are connected by a perforated metal studs and a conductive inner case up and hit the outside of the cabinet a screw, with a screw through the hole, and then ground to the screw, wire bonding to the earth.
How discharge ESD protection circuit
Positively charged human hand to touch the pins of the chip. If the chip is electrically words, the ESD protection circuit will work, provide a discharge path; but if the chip is not powered on, the positive charge will be transferred from the person to the pins of the chip, the positive charge accumulated on the pin What happens then? ESD protection circuit will it work? What will be the impact on the chip?
Chip is vacant, no pin connected to the ground, so there can be a discharge path to earth
Positive charge to bleed it, must be provided to neutralize the negative charge and, because it is passive, does not have a negative charge and to on-chip. Is it a positive charge
on evenly distributed on the chip? The accumulation of so many positive charges should be caused by how the chip kind of impact?
When referring to a general article ESD protection, power is always assumed that the chip, once charged contacting a person pins, the pin will cause the
ESD protection circuit discharge opening. In fact, the chip is not the power charged to reach people pin chip is easy to occur. This
case conditions, ESD protection circuit how it works, how the kind of a discharge path, the charge dissipation gone?
In fact, this is the most basic of ESD protection chip is a problem, but it is hard to figured. . .
IC anti-static anti-static capabilities we are talking generally refers to affect its normal operation suffered by static electricity, if the IC did not work, how do you know whether it is static bash? In fact, the reality is a lot of IC in transport examples of the process and the installation of electrostatic broke. If no suitable means that the electrostatic discharge path, then, regardless of whether the power IC broke are all possible, as some are sensitive or TVS diode can no electrical work! they are quite a ready-protection IC, when suddenly a large external shock voltage (static), electrostatic immediately into the earth, if the ground is not good, even if the ESD protection device is affixed to the same will bash IC, regardless of whether the IC power!