How PCB copy board to enhance anti-static ESD function

- Aug 05, 2016-

PCB board designs can be layered, proper layout and installation to achieve ESD immunity PCB design. In the design process, it can be predicted by design changes limited to changes in the vast majority of components. By adjusting the PCB layout can be a good guard against ESD.

From the human body, the environment and even the electrical equipment inside the PCB copy board PCB copy board to static precision semiconductor chip can cause a variety of injuries, such as through the internal components of the thin insulating layer; damaged gate of the MOSFET and CMOS components; CMOS PCB copy board member is a trigger lock; short circuit reverse bias PN junction; PCB copy board to short-circuit the positive bias PN junction; PCB copy board aluminum melting or welding line within the active device PCB copy board portion. In order to eliminate electrostatic discharge (ESD) of the electronic device interference and sabotage, require a variety of technical means of prevention.

PCB board designs, can be layered, proper layout of the PCB copy board PCB copy board PCB wiring and installation to achieve the anti-ESD design. In the design process, it can be predicted by design changes limited to changes in the vast majority of components. By adjusting the PCB layout, PCB copy board can very well prevent the PCB copy board ESD. Here are some common precautions.

Whenever possible, use a multi-layer PCB, with respect to the double-sided PCB, the ground and power planes, and the closely arranged signal lines - ground spacing can reduce common-mode impedance and inductive coupling, so as to achieve double-sided PCB 1 / 10 to 1/100. Try a signal to each layer are close to a power supply layer or ground layer. For the top and bottom surfaces of both components, with a short cable, and many places filled with high density PCB, consider using the inner line. For double-sided PCB is to use tightly woven power and ground grid. Power line close to the ground, between the vertical and horizontal lines or fill area, as much as possible to the connection. Side of the grid PCB copy board size is less than equal to 60mm, if possible, the grid size should be less than 13mm.

To ensure that every copy board PCB circuit as compact as possible.

As far as possible all the connectors are put aside.

If possible, the power cable from the central PCB copy board card is introduced, and stay away from affected areas directly affected by ESD.

In the lead outside of the chassis connector (easy PCB copy board directly hit ESD) on all PCB layers below, to be placed wide chassis ground or filled polygon, the distance and approximately every 13mm hole used to connect them together.

PCB copy plate was put mounting holes on the edge of the card, around the mounting hole PCB copy board unobstructed top and bottom solder pads connected to the chassis ground.

When the PCB assembly, not any solder coating on the top or bottom of PCB copy board pads. Having an embedded PCB copy board washers to achieve the PCB and the metal chassis PCB copy board / shield or ground plane in close contact with the stent.

In between each layer of the chassis ground and circuit ground, to set the same "Quarantine"; if possible, keep the separation distance of 0.64mm.

The top and bottom of the card PCB copy board installed near the location of the hole every 100mm along the chassis ground circuit and chassis ground connected together with a line width of 1.27mm. These connection points of adjacent, between the chassis ground and circuit ground PCB copy board to place the pad or mounting holes for mounting. The ground connection can be cut open with a blade to keep open, or beads / high frequency capacitance jumper.

If the board does not put the metal chassis or PCB copy board shield apparatus, the circuit board top and bottom of the chassis ground wire solder resist can not be painted, so that they can be used as ESD arc discharge electrode.

To copy the following PCB circuit board column disposed in a ring around the ground:

(1) In addition to the edge connector PCB copy board device and chassis ground, put a ring around the periphery of the entire path to ground.

(2) to ensure that the annular layer is greater than the width of all 2.5mm.

(3) every 13mm hole used to connect the ring together.

(4) the ring with multilayer PCB copy board circuit common connected together.

(5) of the double-sided PCB copy board installed in a metal cabinet or in the shielding device, it should be linked with the ring circuit common ground. Unshielded annular sided circuit should be connected to the chassis, the annular solder resist can not be painted on the ground, so that the ring can act as ESD to discharge rod, in a position circumferentially (all layers) disposed on at least one of 0.5mm gap width, to avoid PCB copy board and form a big loop. Signal wiring distance away from the ring to be not less than 0.5mm.


Previous:BGA pad repair techniques Next:The basic principle requires a printed circuit board design