PCB Circuit Board Fifteen Common Circuit Effects

PCB circuit board fifteen common circuit effects: suspension bridge effect, ripple effect, overshock effect, resonance effect, suspension effect, crosstalk effect, reflection effect, shielding effect, thermal expansion effect, ground hole effect, filling effect, temperature drift effect, crystal effect, limited effect, mine effect.

1. Suspension bridge effect: In the case of high-density wiring, when there is not enough space between the two lines, there may be a situation where one line is suspended on the other line, similar to the suspension bridge shape. The drawbridge effect often occurs in PCB designs, especially when a large number of signal lines need to be laid out and space is limited. The drawbridge effect can cause problems such as signal crosstalk, electromagnetic interference, and signal distortion or delay.

Measures to reduce the drawbridge effect

• Reasonable planning of PCB layout, as far as possible to maintain the linear layout of signal lines, to avoid the occurrence of line crossing or overlapping.
• Optimize PCB routing, maximize the spacing between signal lines, and avoid the drawbridge effect caused by too small space.
• Use circuit board layering design to arrange different signal lines at different levels to reduce cross and interference between lines.
• Reduce electromagnetic interference between signal lines and improve the anti-interference capability of the circuit through appropriate signal layer and stratum planning.

2. Ripple effect: In high-speed circuits, when the signal transmission speed is faster, the signal may produce ripple deformation when propagating on the circuit board, affecting the signal quality, including signal distortion, clock offset, crosstalk and interference.

Measures to reduce ripple effects

• Optimize PCB layout and routing to minimize bending, crossing and branching of signal lines and maintain signal transmission path consistency.
• The use of appropriate signal lines and ground design, reduce the crosstalk and interference between signal lines, improve the quality of signal transmission.
• Use signal compensation technology or signal pre-accentuation technology to compensate and enhance the signal to reduce waveform distortion and deformation.
• Select appropriate signal transmission lines and signal processing devices to improve the anti-interference ability and transmission speed of the signal.

3. Overshoot effect: Sudden voltage changes during signal transmission may lead to excessive voltage impact on components on the circuit board, damaging components or causing circuit failure. The overshoot effect may be caused by the rising or falling edge of the signal too fast, or it may be caused by the instability of the signal transmission line or the instability of the signal source.

Measures to reduce overshoot effects

• Optimize the design of signal transmission lines to ensure impedance matching and stability of signal lines.
• Use suitable power filters and power decoupling capacitors to reduce signal source interference.
• Adopt signal pre-weighting technology or signal compensation technology to pre-process or compensate the signal to reduce the occurrence of overshoot effect.
• Select appropriate components and circuit protection devices to improve the circuit's overshoot resistance and stability.

4. Resonance effect: Parameters such as inductance, capacitance and impedance on the circuit board may cause the signal to resonate at a specific frequency, affecting the stable transmission of the signal. This resonance phenomenon usually occurs at a specific frequency, when the frequency of the external signal matches the natural frequency of the circuit, causing a resonance effect.

Measures to reduce resonance effects

• Optimize PCB layout and design to avoid situations in the circuit where the natural frequency is close to the external excitation frequency.
• Use compensation circuits or filters to eliminate or suppress resonant effects.
• Select appropriate damping elements or damping materials to reduce the impact of resonance effects.
• Use appropriate circuit tuning techniques to stabilize the circuit's frequency response within a specific frequency range.

5. Suspension effect: In high-speed circuits, due to electromagnetic radiation and other factors, the signal may be suspended on the surface of the wire or circuit board, affecting the transmission and reception of the signal. In order to reduce the PCB suspension effect on the circuit, the designer can take the following measures:

Measures to reduce suspension effects

• Optimize PCB layout and design, reasonably plan the direction and spacing of signal lines, and minimize the impact of electromagnetic radiation on signal transmission.
• Use appropriate signal line and ground design to ensure impedance matching and stability of the signal line.
• Use shields or shielding materials to reduce electromagnetic radiation and interference.
• Select appropriate board materials and components to reduce the occurrence of suspension effects.

6. Crosstalk effect: Due to the dense layout between PCB signal lines or electromagnetic interference and other factors, signal crosstalk may occur between different signal lines. Signal crosstalk can cause signal quality degradation or circuit malfunction.

Measures to reduce crosstalk effects

• Optimize PCB layout and design, reasonably plan the direction and spacing of signal lines, and minimize mutual interference between signal lines.
• Use technologies such as shielding enclosures, shielding materials or ground isolation to reduce the impact of electromagnetic interference on the signal.
• Use differential signal transmission lines or add signal layers to improve anti-interference ability and reduce the occurrence of crosstalk effects.
• Select the right board materials and components to reduce the impact of crosstalk effects.

7. Reflection effect: refers to the phenomenon that in high-speed signal transmission, due to the impedance mismatch encountered when the signal is propagated in the PCB line or the terminal of the signal transmission line does not fully absorb the energy of the signal, resulting in the signal reflection back to the original source. This reflection effect may lead to distortion of signal waveform and affect the transmission quality and stability of the circuit.

Measures to reduce reflection effects

• Reasonably design the signal transmission line to ensure the impedance matching of the line and minimize the impedance mismatch.
• Use elements such as terminal resistors or terminal capacitors to absorb signal energy and reduce signal reflection.
• Optimize PCB layout and design to minimize the length of signal transmission lines and reduce signal transmission delays.
• Select the right board materials and components to reduce the impact of reflection effects.

8. Shielding effect: The metal layer or shielding cover on the PCB board may have a shielding effect on the signal, affecting the transmission range and quality of the signal.

Measures to reduce the shielding effect

• Reasonable design of PCB layout: try to avoid overlap or proximity between signal lines and shielded areas to reduce the impact of shielding effects.
• Select the right shielding material: Select the right metal layer or shielding material in the PCB design to make it have good shielding performance while minimizing the impact on signal transmission.
• Design a suitable grounding structure: a good grounding structure can help reduce the shielding effect of the signal and improve the transmission quality of the signal.
• Pay attention to signal adjustment: For signals that need to pass through the shielded area, signal adjustment technology can be used to reduce the influence of the shielding effect, such as increasing the signal power or adjusting the signal transmission mode.

9. Thermal expansion effect: temperature changes may lead to thermal expansion or contraction of PCB board materials, affecting the dimensional stability of the circuit board and the connection status of components.

Measures to reduce the effect of thermal expansion

• Select the right PCB material: Select PCB material with small thermal expansion coefficient can reduce the influence of thermal expansion effect on the circuit.
• Reasonable design of PCB layout: In the PCB design process, try to avoid directly connecting materials with high thermal expansion coefficient and low thermal expansion coefficient to reduce the influence of thermal expansion effect.
• Control the welding temperature: During the welding process, control the welding temperature and time to avoid excessive temperature resulting in solder joint cracking or component displacement.
• The use of support structure: Adding a suitable support structure to the PCB board design can reduce the bending deformation of the PCB board and improve the stability and reliability of the PCB board

10. Ground hole effect: There are a large number of ground holes on the PCB board, and when the distance between the local hole and the signal line or other ground holes is relatively close, the ground hole effect may occur, affecting the stability of signal transmission.

Measures to reduce ground hole effect

• Reasonable design of the ground hole: design appropriate ground hole parameters, such as aperture, hole distance, copper foil diameter, etc., to ensure the impedance matching and consistency of the ground hole, reduce the inductance and crosstalk effect of the ground hole.
• The use of ground hole filling: when designing PCB, the ground hole filling technology can be used to fill the ground hole, reduce the impact of the ground hole on signal transmission, and improve the performance stability of the PCB board.
• Optimize layout: rationally plan PCB layout, minimize the number and density of ground holes, and reduce the influence of ground hole effect on the circuit.
• Adjust interlayer stacking: Choose the interlayer stacking mode of PCB board reasonably, minimize the ground hole between the inner layer and the outer layer, and reduce the influence of the ground hole effect

11. Filling effect: The filling material on the PCB board may have an impact on signal transmission, such as the dielectric constant of the filling material is different, which may cause the signal transmission speed to change or signal attenuation.

Measures to reduce filling effects

• Reasonable selection of filling materials: Select a filling material with a dielectric constant similar to the PCB board material to reduce the impact of dielectric constant differences on signal transmission.
• Control the thickness of the filling material: reasonably control the thickness of the filling material to avoid the extension of the signal transmission path and the increase of attenuation caused by the thickness of the filling material.
• Optimize PCB layout: When designing the PCB, minimize the impact on the signal transmission path, rationally plan the filling area, and avoid the interference of the filling material on the signal transmission path.
• Use low loss filling materials: Select filling materials with low resistance and dielectric loss to reduce attenuation and distortion during signal transmission

12. Temperature drift effect: The temperature change on the PCB board may lead to the thermal expansion or contraction of the circuit board material, which affects the dimensional stability of the circuit board and the connection status of the components.

Measures to reduce the effect of temperature drift

• Reasonable selection of PCB materials: Select PCB materials with good thermal stability and dimensional stability to reduce the impact of temperature changes on the PCB board.
• Control welding temperature: During the welding process, control the welding temperature and time to avoid excessive welding temperature resulting in damage or fracture of components and welding points.
• Optimize PCB layout: rationally plan PCB layout, reduce the difference in thermal expansion coefficient between components, and avoid temperature changes caused by changes in the connection state between components.
• Temperature environment control: Control the temperature change in the PCB use environment, avoid the PCB board by a large temperature impact, and reduce the impact of temperature changes on the PCB circuit.

13. Crystal effect: Devices such as transistors in PCB wiring may be affected by the surrounding environment, resulting in changes in device parameters and affecting the performance of the circuit.

Measures to reduce crystal effects

• Reasonable layout: Reasonable planning of PCB layout to avoid the influence of external interference on devices such as transistors and minimize the interference of electromagnetic fields on devices.
• Temperature control: In the PCB design and manufacturing process, measures are taken to control the operating temperature of the PCB board, reduce the impact of temperature changes on the device parameters, and improve the stability of the circuit.
• Select the right device: Select devices such as transistors with good anti-interference and stability to reduce the impact of crystal effects on the circuit.
• Design compensation circuit: In PCB design, compensation circuit can be used to correct the drift of device parameters such as transistors and improve the performance and stability of the circuit

14. Limited effect: There are some restricted areas on the PCB board, such as edges, power supply areas, etc., which may cause certain restrictions or effects on signal transmission or wiring.

Measures to reduce limiting effects

• Reasonable planning and layout: In PCB design, reasonable planning and layout should be carried out to avoid placing sensitive signal lines or components near restricted areas to reduce the impact of restrictions.
• Electromagnetic shielding: For the restricted area is vulnerable to electromagnetic interference, electromagnetic shielding measures can be taken, such as metal shielding around the sensitive area to reduce the impact of external electromagnetic interference on the circuit.
• Optimize the power supply design: For the power supply instability or noise problems that may exist in the power supply area, measures can be taken to optimize the power supply design, such as increasing the filter circuit, reducing the power supply noise, etc., to improve the power supply stability and performance of the circuit.
• Fine wiring: When wiring in a restricted area, try to use fine wiring to reduce the limitation or extension of the signal transmission path, and improve the rate and stability of signal transmission

15. Mine effect: Invisible problems or hidden faults on the PCB board may suddenly appear in the subsequent test or use process, bringing unexpected impact or damage to the circuit board.

Measures to reduce the effects of landmines

• Strict quality control: In the PCB production process, the quality of each link is strictly controlled to ensure that each component and circuit connection meet the specifications and reduce hidden dangers.
• Improve the test process: Establish a sound test and inspection process, conduct a comprehensive test and inspection of PCB circuits, and timely find and repair potential problems.
• Use reliable components: Select components and materials with high reliability and stable quality to reduce the probability of failure and reduce the occurrence of mine effects.
• Intensive maintenance: Regular maintenance and maintenance of the PCB circuit that has been produced, timely detection and repair of potential problems, improve the reliability and stability of the circuit.