PCB design anti-static discharge method
Release date:2016-07-08 Views 199
PCB design anti-static discharge method
Kunshan PCB board designs, can be layered, proper layout and installation to achieve ESD immunity PCB design. By adjusting the Kunshan PCB layout can be a good guard against ESD as a multilayer PCB, with respect to the double-sided PCB, the ground and power planes, and the closely arranged signal lines - ground can reduce common mode spacing impedance and inductive coupling, so as to achieve double-sided PCB 1/10 to 1/100 for the top and bottom surfaces of both components, with a short cable.
From the human body, the environment and even electronic equipment within the static precision for semiconductor chips 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 devices trigger lock ; short-circuit reverse bias PN junction; short-circuit forward-biased PN junction; melting active devices inside the welding wire or aluminum. In order to eliminate electrostatic discharge (ESD) of the electronic device interference and sabotage, require a variety of technical means of prevention.
Kunshan PCB 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. 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 to be a signal of 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. One side of the grid size is less than equal to 60mm, if possible, the grid size should be less than 13mm. Ensure that each circuit as compact as possible.
As far as possible all the connectors are on the side
If possible, the power cable from the central card is introduced, and stay away from affected areas directly affected by ESD.
In the lead outside of the chassis connector (easily hit directly by 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.
Place the mounting holes on the edge of the card, with unimpeded around the mounting hole solder pads connected to the top and bottom of the chassis ground.
When the PCB assembly, not any solder coating on the top or bottom of the pad. Having a built-in washers to achieve the PCB and the metal chassis / 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, to maintain a distance of 0.64mm spacing position in the top and bottom of the card near mounting holes every 100mm along the chassis ground cable and chassis ground circuit connected together with a line width of 1.27mm. These connection points adjacent to, and in between the chassis ground circuit pad or placing 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 will not be placed in a metal box or shielding device, the board of the 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 the following manner in a ring around the circuit to:
(1) In addition to the edge connector 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 the public to multilayer circuits connected together.
(5) mounted on a metal chassis or shielding device in dual-panel, 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 forming a large loop. Signal wiring distance away from the ring to be not less than 0.5mm. ESD can be a direct hit in a region near each signal line should be a ground cloth.
I / O circuit as close as possible to the corresponding connector
On ESD-susceptible circuits, it should be placed near the center of the region of the circuit, so that other circuits may provide some shielding effect for them.
Usually at the receiving end and bead placing resistors in series, and for those susceptible to ESD cable driver hit, you can also consider placing resistors in series or beads at the drive end.
Usually placed at the receiving end of transient protector. Short and thick lines (length times width is less than 5, preferably less than 3 times the width) is connected to the chassis ground. From the connector out to the signal line and ground directly to the transient protection before it can access other parts of the circuit.
At the connector or from within the range of 25mm reception circuit, filter capacitor to be placed:
(1) with a short, thick line is connected to the chassis or in the receiving circuit ground (length times width of less than 5, preferably less than 3 times the width).
(2) the signal and ground lines connected to the first capacitor and then connected to the receiving circuit.
To ensure that the signal lines as short as possible
When the length of the signal line is larger than 300mm, a cloth must be parallel to the ground.
Make sure the loop between the signal line and a corresponding loop area as small as possible. For every few centimeters long signal line will have to swap the location of the signal line and ground to reduce the loop area.
Into the plurality of receiving circuits center position of the drive signal from the network
Make sure the loop area between power and ground as small as possible, placing a high frequency integrated circuit chip capacitor near the power pin of each place.
Into the plurality of receiving circuits center position of the drive signal from the network
Where possible, the land to fill unused areas, 60mm away from every land will fill all the layers are connected.
Ensure filled arbitrarily large area (greater than approximately 25mm × 6mm) of the two opposite end positions to be connected to the ground.
Both sides of the length exceeds 8mm, use a narrow line of the opening of the opening connecting the power or ground plane.
Reset line interrupt signal line or edge-triggered signal line can not be arranged in a place near the edge of the PCB.
The mounting holes connected with the circuit commons together or isolate them
(1) metal stent and metal shielding means must be used together or enclosure, to the use of a zero-ohm resistor connected.
(2) to determine the size of the mounting holes to achieve reliable installation of metal or plastic stents, on the top and bottom mounting holes to be used large pad can not be used on the solder resist layer pads, and make sure the bottom of the pad without using wave soldering processes welding.
The signal can not be protected and unprotected lines signal lines arranged in parallel.
Pay special attention to reset, interrupt control and signal lines wiring
(1) for a high frequency filter.
(2) away from the input and output circuits.
(3) away from the edge of the board.
PCB to be inserted into the chassis, do not install or open position inside seams
Note that under the bead wire, and between the pads may be exposed to magnetic beads signal lines. Some beads quite good conductive properties, may have unintended conductive path.
If a chassis or motherboard to be built a few circuit boards, will be the most sensitive to static electricity board in the middle.
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Kunshan PCB board designs, can be layered, proper layout and installation to achieve ESD immunity PCB design. By adjusting the Kunshan PCB layout can be a good guard against ESD as a multilayer PCB, with respect to the double-sided PCB, the ground and power planes, and the closely arranged signal lines - ground can reduce common mode spacing impedance and inductive coupling, so as to achieve double-sided PCB 1/10 to 1/100 for the top and bottom surfaces of both components, with a short cable.
From the human body, the environment and even electronic equipment within the static precision for semiconductor chips 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 devices trigger lock ; short-circuit reverse bias PN junction; short-circuit forward-biased PN junction; melting active devices inside the welding wire or aluminum. In order to eliminate electrostatic discharge (ESD) of the electronic device interference and sabotage, require a variety of technical means of prevention.
Kunshan PCB 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. 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 to be a signal of 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. One side of the grid size is less than equal to 60mm, if possible, the grid size should be less than 13mm. Ensure that each circuit as compact as possible.
As far as possible all the connectors are on the side
If possible, the power cable from the central card is introduced, and stay away from affected areas directly affected by ESD.
In the lead outside of the chassis connector (easily hit directly by 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.
Place the mounting holes on the edge of the card, with unimpeded around the mounting hole solder pads connected to the top and bottom of the chassis ground.
When the PCB assembly, not any solder coating on the top or bottom of the pad. Having a built-in washers to achieve the PCB and the metal chassis / 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, to maintain a distance of 0.64mm spacing position in the top and bottom of the card near mounting holes every 100mm along the chassis ground cable and chassis ground circuit connected together with a line width of 1.27mm. These connection points adjacent to, and in between the chassis ground circuit pad or placing 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 will not be placed in a metal box or shielding device, the board of the 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 the following manner in a ring around the circuit to:
(1) In addition to the edge connector 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 the public to multilayer circuits connected together.
(5) mounted on a metal chassis or shielding device in dual-panel, 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 forming a large loop. Signal wiring distance away from the ring to be not less than 0.5mm. ESD can be a direct hit in a region near each signal line should be a ground cloth.
I / O circuit as close as possible to the corresponding connector
On ESD-susceptible circuits, it should be placed near the center of the region of the circuit, so that other circuits may provide some shielding effect for them.
Usually at the receiving end and bead placing resistors in series, and for those susceptible to ESD cable driver hit, you can also consider placing resistors in series or beads at the drive end.
Usually placed at the receiving end of transient protector. Short and thick lines (length times width is less than 5, preferably less than 3 times the width) is connected to the chassis ground. From the connector out to the signal line and ground directly to the transient protection before it can access other parts of the circuit.
At the connector or from within the range of 25mm reception circuit, filter capacitor to be placed:
(1) with a short, thick line is connected to the chassis or in the receiving circuit ground (length times width of less than 5, preferably less than 3 times the width).
(2) the signal and ground lines connected to the first capacitor and then connected to the receiving circuit.
To ensure that the signal lines as short as possible
When the length of the signal line is larger than 300mm, a cloth must be parallel to the ground.
Make sure the loop between the signal line and a corresponding loop area as small as possible. For every few centimeters long signal line will have to swap the location of the signal line and ground to reduce the loop area.
Into the plurality of receiving circuits center position of the drive signal from the network
Make sure the loop area between power and ground as small as possible, placing a high frequency integrated circuit chip capacitor near the power pin of each place.
Into the plurality of receiving circuits center position of the drive signal from the network
Where possible, the land to fill unused areas, 60mm away from every land will fill all the layers are connected.
Ensure filled arbitrarily large area (greater than approximately 25mm × 6mm) of the two opposite end positions to be connected to the ground.
Both sides of the length exceeds 8mm, use a narrow line of the opening of the opening connecting the power or ground plane.
Reset line interrupt signal line or edge-triggered signal line can not be arranged in a place near the edge of the PCB.
The mounting holes connected with the circuit commons together or isolate them
(1) metal stent and metal shielding means must be used together or enclosure, to the use of a zero-ohm resistor connected.
(2) to determine the size of the mounting holes to achieve reliable installation of metal or plastic stents, on the top and bottom mounting holes to be used large pad can not be used on the solder resist layer pads, and make sure the bottom of the pad without using wave soldering processes welding.
The signal can not be protected and unprotected lines signal lines arranged in parallel.
Pay special attention to reset, interrupt control and signal lines wiring
(1) for a high frequency filter.
(2) away from the input and output circuits.
(3) away from the edge of the board.
PCB to be inserted into the chassis, do not install or open position inside seams
Note that under the bead wire, and between the pads may be exposed to magnetic beads signal lines. Some beads quite good conductive properties, may have unintended conductive path.
If a chassis or motherboard to be built a few circuit boards, will be the most sensitive to static electricity board in the middle.
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