Does it matter what size of via you use in high frequency circuits?
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Here is an image of an LNB and there is some different "Via"s in the PCB that I don't know Why do they use different size of Vias in such circuits. Why? Any reason?
I showed two Vias using two arrows that are close each other(Right side of the image).
pcb-design high-frequency
add a comment |
up vote
7
down vote
favorite
Here is an image of an LNB and there is some different "Via"s in the PCB that I don't know Why do they use different size of Vias in such circuits. Why? Any reason?
I showed two Vias using two arrows that are close each other(Right side of the image).
pcb-design high-frequency
1
larger vias have wider aspect ratio, thus lower inductance
– analogsystemsrf
Nov 27 at 12:17
1
@analogsystemsrf Okay, But why two different vias on a PCB?
– Roh
Nov 27 at 12:20
Relevant because same board and OP: electronics.stackexchange.com/questions/409083/…
– pipe
Nov 27 at 15:08
add a comment |
up vote
7
down vote
favorite
up vote
7
down vote
favorite
Here is an image of an LNB and there is some different "Via"s in the PCB that I don't know Why do they use different size of Vias in such circuits. Why? Any reason?
I showed two Vias using two arrows that are close each other(Right side of the image).
pcb-design high-frequency
Here is an image of an LNB and there is some different "Via"s in the PCB that I don't know Why do they use different size of Vias in such circuits. Why? Any reason?
I showed two Vias using two arrows that are close each other(Right side of the image).
pcb-design high-frequency
pcb-design high-frequency
asked Nov 27 at 12:13
Roh
2,80052765
2,80052765
1
larger vias have wider aspect ratio, thus lower inductance
– analogsystemsrf
Nov 27 at 12:17
1
@analogsystemsrf Okay, But why two different vias on a PCB?
– Roh
Nov 27 at 12:20
Relevant because same board and OP: electronics.stackexchange.com/questions/409083/…
– pipe
Nov 27 at 15:08
add a comment |
1
larger vias have wider aspect ratio, thus lower inductance
– analogsystemsrf
Nov 27 at 12:17
1
@analogsystemsrf Okay, But why two different vias on a PCB?
– Roh
Nov 27 at 12:20
Relevant because same board and OP: electronics.stackexchange.com/questions/409083/…
– pipe
Nov 27 at 15:08
1
1
larger vias have wider aspect ratio, thus lower inductance
– analogsystemsrf
Nov 27 at 12:17
larger vias have wider aspect ratio, thus lower inductance
– analogsystemsrf
Nov 27 at 12:17
1
1
@analogsystemsrf Okay, But why two different vias on a PCB?
– Roh
Nov 27 at 12:20
@analogsystemsrf Okay, But why two different vias on a PCB?
– Roh
Nov 27 at 12:20
Relevant because same board and OP: electronics.stackexchange.com/questions/409083/…
– pipe
Nov 27 at 15:08
Relevant because same board and OP: electronics.stackexchange.com/questions/409083/…
– pipe
Nov 27 at 15:08
add a comment |
1 Answer
1
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votes
up vote
7
down vote
accepted
Vias have inductance and the more spindly they are, the larger the inductance. Note that in the equation above, inductance is proportional to the height of the via multiplied by the formula in the square brackets. That square bracket formula result is smaller when dimension $d$ is larger hence, inductance drops with larger diameter vias.
Picture from this website.
You also can't rule out parallel resonance with its parasitic capacitance either. The inductance and capacitance of the via form a parallel tuned circuit and, that could block a high frequency component of a signal in some cases. Using two different via sizes side-by-side might be the way the designer had in mind of "spoiling" the resonances.
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
7
down vote
accepted
Vias have inductance and the more spindly they are, the larger the inductance. Note that in the equation above, inductance is proportional to the height of the via multiplied by the formula in the square brackets. That square bracket formula result is smaller when dimension $d$ is larger hence, inductance drops with larger diameter vias.
Picture from this website.
You also can't rule out parallel resonance with its parasitic capacitance either. The inductance and capacitance of the via form a parallel tuned circuit and, that could block a high frequency component of a signal in some cases. Using two different via sizes side-by-side might be the way the designer had in mind of "spoiling" the resonances.
add a comment |
up vote
7
down vote
accepted
Vias have inductance and the more spindly they are, the larger the inductance. Note that in the equation above, inductance is proportional to the height of the via multiplied by the formula in the square brackets. That square bracket formula result is smaller when dimension $d$ is larger hence, inductance drops with larger diameter vias.
Picture from this website.
You also can't rule out parallel resonance with its parasitic capacitance either. The inductance and capacitance of the via form a parallel tuned circuit and, that could block a high frequency component of a signal in some cases. Using two different via sizes side-by-side might be the way the designer had in mind of "spoiling" the resonances.
add a comment |
up vote
7
down vote
accepted
up vote
7
down vote
accepted
Vias have inductance and the more spindly they are, the larger the inductance. Note that in the equation above, inductance is proportional to the height of the via multiplied by the formula in the square brackets. That square bracket formula result is smaller when dimension $d$ is larger hence, inductance drops with larger diameter vias.
Picture from this website.
You also can't rule out parallel resonance with its parasitic capacitance either. The inductance and capacitance of the via form a parallel tuned circuit and, that could block a high frequency component of a signal in some cases. Using two different via sizes side-by-side might be the way the designer had in mind of "spoiling" the resonances.
Vias have inductance and the more spindly they are, the larger the inductance. Note that in the equation above, inductance is proportional to the height of the via multiplied by the formula in the square brackets. That square bracket formula result is smaller when dimension $d$ is larger hence, inductance drops with larger diameter vias.
Picture from this website.
You also can't rule out parallel resonance with its parasitic capacitance either. The inductance and capacitance of the via form a parallel tuned circuit and, that could block a high frequency component of a signal in some cases. Using two different via sizes side-by-side might be the way the designer had in mind of "spoiling" the resonances.
edited Nov 27 at 12:28
answered Nov 27 at 12:23
Andy aka
236k10173401
236k10173401
add a comment |
add a comment |
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1
larger vias have wider aspect ratio, thus lower inductance
– analogsystemsrf
Nov 27 at 12:17
1
@analogsystemsrf Okay, But why two different vias on a PCB?
– Roh
Nov 27 at 12:20
Relevant because same board and OP: electronics.stackexchange.com/questions/409083/…
– pipe
Nov 27 at 15:08